MCAsmLexer.h has been made a forwarder header since #134207

We can use "constexpr if" to combine the two variants of functions.

We can use "constexpr if" to combine the two variants of functions.

Simplfy `cond ? val : false` to `cond && val` and similar.

Identified with misc-include-cleaner.

Walks over the MCExpr and uses KnownBits to deduce whether an expression
is known and if so, prints said known value. Should support the most
common MCExpr cases for AMDGPU metadata.

Allows MCExprs as passed values to PALMetadata. Also adds related
`DelayedMCExpr` classes which serve as a pseudo-fixup to resolve MCExprs
as late as possible (i.e., right before emit through string or blob,
where they should be resolvable).

Redefines the amd_kernel_code_t struct with MCExprs for members that would be
derived from SIProgramInfo MCExpr members.

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

C++17 allows us to call constructors pair and tuple instead of helper
functions make_pair and make_tuple.

Differential Revision: https://reviews.llvm.org/D139828