Use deduction guides instead of helper functions.

The only non-automatic changes have been:

1. ArrayRef(some_uint8_pointer, 0) needs to be changed into ArrayRef(some_uint8_pointer, (size_t)0) to avoid an ambiguous call with ArrayRef((uint8_t*), (uint8_t*))
2. CVSymbol sym(makeArrayRef(symStorage)); needed to be rewritten as CVSymbol sym{ArrayRef(symStorage)}; otherwise the compiler is confused and thinks we have a (bad) function prototype. There was a few similar situation across the codebase.
3. ADL doesn't seem to work the same for deduction-guides and functions, so at some point the llvm namespace must be explicitly stated.
4. The "reference mode" of makeArrayRef(ArrayRef<T> &) that acts as no-op is not supported (a constructor cannot achieve that).

Per reviewers' comment, some useless makeArrayRef have been removed in the process.

This is a follow-up to https://reviews.llvm.org/D140896 that introduced
the deduction guides.

Differential Revision: https://reviews.llvm.org/D140955

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716

`llvm` and downstream internal callers no longer use `array_lengthof`, so drop
the include everywhere.

Differential Revision: https://reviews.llvm.org/D133600

LLVM contains a helpful function for getting the size of a C-style
array: `llvm::array_lengthof`. This is useful prior to C++17, but not as
helpful for C++17 or later: `std::size` already has support for C-style
arrays.

Change call sites to use `std::size` instead.

Differential Revision: https://reviews.llvm.org/D133429

Check ScopedPrinter pointer before attempting to print the attribute's
parsed information.

Patch by Michael Platings and Victor Campos

Reviewed By: pratlucas

Differential Revision: https://reviews.llvm.org/D132214

The ARM Attribute Parser used to parse the value of also_compatible_with
as it is, disregarding the way it is encoded.

This patch does a context aware parsing of the also_compatible_with
attribute. Additionally, some error handling is also done for incorrect
cases.

Reviewed By: pratlucas

Differential Revision: https://reviews.llvm.org/D130913

The ARM attribute parser for Tag_CPU_arch is missing value descriptions
for Armv8-A and Armv8-R.

This patch adds these descriptions.

Reviewed By: pratlucas

Differential Revision: https://reviews.llvm.org/D129631

The build attribute number can be found in the Arm ABI addenda32 document:
https://github.com/ARM-software/abi-aa/blob/main/addenda32/addenda32.rst#335target-related-attributes

Reviewed By: tmatheson

Differential Revision: https://reviews.llvm.org/D124090