This was already declared in NVPTX.h and I accidentally added it back in
#134416.

The NVVMReflect pass simply replaces calls to nvvm-reflect functions
with the appropriate constant, either the architecture number, or
nvvm-reflect-ftz, found in the module's metadata.

The implementation is inefficient and does this by traversing through
all instructions to find calls. The common case is that you never call
nvvm-reflect, so this traversal is costly.

This PR:
- Updates the pass so that it finds the reflect functions by name, and
then traverses through their uses to find the calls directly.
- Adds a line (245) to make sure the dead nvvm-reflect definitions are
erased.
- Adds the ability to set reflect values via command line

- Move all pass initialization function calls to NVPTX target
initialization and out of individual pass constructors.
- Move all pass initialization function declaration to NVPTX.h.
- https://github.com/llvm/llvm-project/issues/111767

Summary:
Test uses nvptx in 32-bit mode and calling `mcpu` is broken and caused
asan failures.

This patch fixes:

  llvm/lib/Target/NVPTX/NVVMReflect.cpp:225:18: error: object backing
  the pointer will be destroyed at the end of the full-expression
  [-Werror,-Wdangling-gsl]

Summary:
This pass lowers the `__nvvm_reflect` builtin in the IR. However, this
currently runs in the standard optimization pipeline, not just the
backend pipeline. This means that if the user creates LLVM-IR without an
architecture set, it will always delete the reflect code even if it is
intended to be used later.

Pushing this into the backend pipeline will ensure that this works as
intended, allowing users to conditionally include code depending on
which target architecture the user ended up using. This fixes a bug in
OpenMP and missing code in `libc`.

Identified with misc-include-cleaner.

Similar to https://github.com/llvm/llvm-project/pull/96902, this adds
`getDataLayout()` helpers to Function and GlobalValue, replacing the
current `getParent()->getDataLayout()` pattern.