[llvm] properly guard dump methods in Support lib classes (#139938)

## Purpose
Add proper preprocessor guards for all `dump()` methods in the LLVM
support library. This change ensures these methods are not part of the
public ABI for release builds.

## Overview
* Annotates all `dump` methods in Support and ADT source with the
`LLVM_DUMP_METHOD` macro.
* Conditionally includes all `dump` method definitions in Support and
ADT source so they are only present on debug/assert builds and when
`LLVM_ENABLE_DUMP` is explicitly defined.

NOTE: For many of these `dump` methods, the implementation was already
properly guarded but the declaration in the header file was not.

## Background
This PR is a redo of #139804 with some changes to fix clang and unit
test build breaks.

This issue was raised in comments on #136629. I am addressing it as a
separate change since it is independent from the changes being made in
that PR.

According to [this
documentation](https://github.com/llvm/llvm-project/blob/main/llvm/include/llvm/Support/Compiler.h#L637),
`dump` methods should be annotated with `LLVM_DUMP_METHOD` and
conditionally included as follows:
```
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
  LLVM_DUMP_METHOD void dump() const;
#endif
```

## Validation
* Local release build succeeds.
* CI

0 files changed, 0 insertions, 0 deletions