This patch fixes a couple of places where memprof-related metadata
(!memprof and !callsite) were being dropped, and one place where PGO
metadata (!prof) was being dropped.

All were due to instances of combineMetadata() being invoked. That
function drops all metadata not in the list provided by the client, and
also drops any not in its switch statement.

Memprof metadata needed a case in the combineMetadata switch statement.
For now we simply keep the metadata of the instruction being kept, which
doesn't retain all the profile information when two calls with
memprof metadata are being combined, but at least retains some.

For the memprof metadata being dropped during call CSE, add memprof and
callsite metadata to the list of known ids in combineMetadataForCSE.

Neither memprof nor regular prof metadata were in the list of known ids
for the callsite in MemCpyOptimizer, which was added to combine AA
metadata after optimization of byval arguments fed by memcpy
instructions, and similar types of optimizations of memcpy uses.

There is one other callsite of combineMetadata, but it is only invoked
on load instructions, which do not carry these types of metadata.

This PR is motivated by a mismatch we discovered between compilation
results with vs. without `-g3`. We noticed this when compiling SPEC2017
testcases. The specific instance we saw is fixed in this PR by modifying
a guard (see below), but it is likely similar instances exist elsewhere
in the codebase.

The specific case fixed in this PR manifests itself in the `SimplifyCFG`
pass doing different things depending on whether DebugInfo is generated
or not. At the end of this comment, there is reduced example code that
shows the behavior in question.

The differing behavior has two root causes:
1. Commit https://github.com/llvm/llvm-project/commit/c07e19b adds loop
metadata including debug locations to loops that otherwise would not
have loop metadata
2. Commit https://github.com/llvm/llvm-project/commit/ac28efa6c100 adds
a guard to a simplification action in `SImplifyCFG` that prevents it
from simplifying away loop metadata

So, the change in 2. does not consider that when compiling with debug
symbols, loops that otherwise would not have metadata that needs
preserving, now have debug locations in their loop metadata. Thus, with
`-g3`, `SimplifyCFG` behaves differently than without it.

The larger issue is that while debug info is not supposed to influence
the final compilation result, commits like 1. blur the line between what
is and is not debug info, and not all optimization passes account for
this.

This PR does not address that and rather just modifies this particular
guard in order to restore equivalent behavior between debug and
non-debug builds in this one instance.

---

Here is a reduced version of a file from `f526.blender_r` that showcases
the behavior in question:
```C
struct LinkNode;
typedef struct LinkNode {
 struct LinkNode *next;
 void *link;
} LinkNode;

void do_projectpaint_thread_ph_v_state() {
  int *ps = do_projectpaint_thread_ph_v_state;
  LinkNode *node;
  while (do_projectpaint_thread_ph_v_state)
    for (node = ps; node; node = node->next)
      ;
}
```
Compiling this with and without DebugInfo, and then disassembling the
results, leads to different outcomes (tested on SystemZ and X86). The
reason for this is that the `SimplifyCFG` pass does different things in
either case.

Remove check for PHI in pred as pointed out in #103688 
Reduced the testcase to remove redundant phi in pred

Fixes: #102351

Preserve !alias.scope, !noalias and !mem.parallel_loop_access metadata
on the replacement instruction, if it does not move. In that case, the
program would be UB, if the aliasing property encoded in the metadata
does not hold. This makes use of the clarification re aliasing metadata
implying UB if the property does not hold: #116220

Same as #115868, but for !alias.scope, !noalias and
!mem.parallel_loop_access.


PR: https://github.com/llvm/llvm-project/pull/117716

This should act like range.

Previously ConstantRangeList assumed a 64-bit range. Now query from the
actual entries. This also means that the empty range has no bitwidth, so
move asserts to avoid checking the bitwidth of empty ranges.

Preserve tbaa metadata on the replacement instruction, if it does not
move. In that case, the program would be UB, if the aliasing property
encoded in the metadata does not hold.

This makes use of the clarification re tbaa metadata implying UB if the
property does not hold: https://github.com/llvm/llvm-project/pull/116220

Same as https://github.com/llvm/llvm-project/pull/115868, but for !tbaa

PR: https://github.com/llvm/llvm-project/pull/116682

Preserve llvm.access.group metadata on the replacement instruction, if
it does not move. In that case, the program would be UB, if the parallel
property encoded in the metadata does not hold.

This matches the LangRef recently updated in #116220

PR https://github.com/llvm/llvm-project/pull/115868

Note that PointerUnion::{is,get,dyn_cast} have been soft deprecated in
PointerUnion.h:

  // FIXME: Replace the uses of is(), get() and dyn_cast() with
  //        isa<T>, cast<T> and the llvm::dyn_cast<T>