Reverts llvm/llvm-project#139804

## 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 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

Exposed by the test added in the reverted #120514

* Fix libstdc++/libc++ differences due to nth_element. https://github.com/llvm/llvm-project/pull/125450#issuecomment-2631404178
* Fix LLVM_ENABLE_REVERSE_ITERATION=1 differences
* Fix potential issue in `currentSize += D::getSize(*sections[*sectionIdxs.begin()])` where DenseSet was used, though not covered by a test

Without these explicit includes, removing other headers, who implicitly
include llvm-config.h, may have non-trivial side effects.

Remove the unused parameter `RecDepth` from `runIterations()`.

The base class llvm::ThreadPoolInterface will be renamed
llvm::ThreadPool in a subsequent commit.

This is a breaking change: clients who use to create a ThreadPool must
now create a DefaultThreadPool instead.

This reverts commit 5954b9dca21bb0c69b9e991b2ddb84c8b05ecba3
due to broken Windows build

Adding weights to utility nodes in BP so that we can give more
importance to
certain utilities. This is useful when we optimize several objectives
jointly.