This MR adds support for the `exact` flag to the
`arith.shrui/shrsi/divsi/divui` operations. The semantics are identical
to those of the LLVM dialect and the LLVM language reference.

This MR also modifies the mechanism for converting `arith` dialect
**attributes** to corresponding **properties** in the `LLVM` dialect.
(As a specific example, the integer overflow flags `nsw/nuw` are
**properties** in the `LLVM` dialect, as opposed to attributes.)

Previously, attribute converter classes were required to have a specific
method to support integer overflow flags:
```C++
template <typename SourceOp, typename TargetOp>
class AttrConvertPassThrough {
public:
  ...
  LLVM::IntegerOverflowFlags getOverflowFlags() const {
    return LLVM::IntegerOverflowFlags::none;
  }
};
```
This method was required, even for `arith` source operations that did
not use integer overflow flags (e.g. `AttrConvertFastMathToLLVM`).

This MR modifies the interface required by `arith` dialect attribute
converters to instead provide a (possibly NULL) properties attribute:
```C++
template <typename SourceOp, typename TargetOp>
class AttrConvertPassThrough {
public:
  ...
  Attribute getPropAttr() const { return {}; }
};
```
For `arith` operations with attributes that map to `LLVM` dialect
**properties**, the attribute converter can create a `DictionaryAttr`
containing target properties and return that attribute from the
attribute converter's `getPropAttr()` method. The `arith` attribute
conversion framework will set the `propertiesAttr` of an
`OperationState`, and the target operation's `setPropertiesFromAttr()`
method will be invoked to set the properties when the target operation
is created. The `AttrConvertOverflowToLLVM` class in this MR uses the
new approach.

See https://github.com/llvm/llvm-project/pull/147168 for more info.

Reverts llvm/llvm-project#125148

bot failures

`arith.bitcast` is allowed on memrefs and such code can actually be
generated by IREE `ConvertBf16ArithToF32Pass`.
`LLVM::detail::vectorOneToOneRewrite` doesn't properly check its types
and will generate bitcast between structs which is illegal.

With the opaque pointers this is a no-op operation for memref so we can
just add type check in `LLVM::detail::vectorOneToOneRewrite` and add a
separate pattern which removes op if converted types are the same.

LLVM itself is generally moving away from using `undef` and towards
using `poison`, to the point of having a lint that caches new uses of
`undef` in tests.

In order to not trip the lint on new patterns and to conform to the
evolution of LLVM
- Rename valious ::undef() methods on StructBuilder subclasses to
::poison()
- Audit the uses of UndefOp in the MLIR libraries and replace almost all
of them with PoisonOp

The remaining uses of `undef` are initializing `uninitialized` memrefs,
explicit conversions to undef from SPIR-V, and a few cases in
AMDGPUToROCDL where usage like

    %v = insertelement <M x iN> undef, iN %v, i32 0
    %arg = bitcast <M x iN> %v to i(M * N)

is used to handle "i32" arguments that are are really packed vectors of
smaller types that won't always be fully initialized.

This PR changes the LLVM dialect's IntegerOverflowFlags to be stored on
operations as native properties.

Reland to fix flang

Reverts llvm/llvm-project#89312 as it breaks all flang buildbots

This PR changes the LLVM dialect's IntegerOverflowFlags to be stored on
operations as native properties.

ConversionPatterns do not (and should not) modify the type converter that they are using.

* Make `ConversionPattern::typeConverter` const.
* Make member functions of the `LLVMTypeConverter` const.
* Conversion patterns take a const type converter.
* Various helper functions (that are called from patterns) now also take a const type converter.

Differential Revision: https://reviews.llvm.org/D157601

The MLIR classes Type/Attribute/Operation/Op/Value support
cast/dyn_cast/isa/dyn_cast_or_null functionality through llvm's doCast
functionality in addition to defining methods with the same name.
This change begins the migration of uses of the method to the
corresponding function call as has been decided as more consistent.

Note that there still exist classes that only define methods directly,
such as AffineExpr, and this does not include work currently to support
a functional cast/isa call.

Caveats include:
- This clang-tidy script probably has more problems.
- This only touches C++ code, so nothing that is being generated.

Context:
- https://mlir.llvm.org/deprecation/ at "Use the free function variants
  for dyn_cast/cast/isa/…"
- Original discussion at https://discourse.llvm.org/t/preferred-casting-style-going-forward/68443

Implementation:
This first patch was created with the following steps. The intention is
to only do automated changes at first, so I waste less time if it's
reverted, and so the first mass change is more clear as an example to
other teams that will need to follow similar steps.

Steps are described per line, as comments are removed by git:
0. Retrieve the change from the following to build clang-tidy with an
   additional check:
   https://github.com/llvm/llvm-project/compare/main...tpopp:llvm-project:tidy-cast-check
1. Build clang-tidy
2. Run clang-tidy over your entire codebase while disabling all checks
   and enabling the one relevant one. Run on all header files also.
3. Delete .inc files that were also modified, so the next build rebuilds
   them to a pure state.
4. Some changes have been deleted for the following reasons:
   - Some files had a variable also named cast
   - Some files had not included a header file that defines the cast
     functions
   - Some files are definitions of the classes that have the casting
     methods, so the code still refers to the method instead of the
     function without adding a prefix or removing the method declaration
     at the same time.

```
ninja -C $BUILD_DIR clang-tidy

run-clang-tidy -clang-tidy-binary=$BUILD_DIR/bin/clang-tidy -checks='-*,misc-cast-functions'\
               -header-filter=mlir/ mlir/* -fix

rm -rf $BUILD_DIR/tools/mlir/**/*.inc

git restore mlir/lib/IR mlir/lib/Dialect/DLTI/DLTI.cpp\
            mlir/lib/Dialect/Complex/IR/ComplexDialect.cpp\
            mlir/lib/**/IR/\
            mlir/lib/Dialect/SparseTensor/Transforms/SparseVectorization.cpp\
            mlir/lib/Dialect/Vector/Transforms/LowerVectorMultiReduction.cpp\
            mlir/test/lib/Dialect/Test/TestTypes.cpp\
            mlir/test/lib/Dialect/Transform/TestTransformDialectExtension.cpp\
            mlir/test/lib/Dialect/Test/TestAttributes.cpp\
            mlir/unittests/TableGen/EnumsGenTest.cpp\
            mlir/test/python/lib/PythonTestCAPI.cpp\
            mlir/include/mlir/IR/
```

Differential Revision: https://reviews.llvm.org/D150123