This PR introduces `amdgpu-lower-exec-sync` pass which specifically
lowers named-barrier LDS globals introduced by #114550 .

Changes include:

- Moving the logic of lowering named-barrier LDS globals from
`amdgpu-lower-module-lds` pass to this new pass.

- This PR adds the pass to pipeline, remove the existing lowering logic for
named-barrier LDS in `amdgpu-lower-module-lds`

See #161827 for discussion on this topic.

Make the test for when additional variables can be added to the struct
allocated at address zero more stringent. Previously, variables can be
added to it (for faster access) even when that increases the lds
requested by a kernel. This corrects that oversight.

Test case diff shows the change from all variables being allocated into
the module lds to only some being, in particular the introduction of
uses of the offset table and that some kernels now use less lds than
before.

Alternative to PR 160181

Saves around 125-210 MB of compilation memory usage per source for
roughly one third of our backend sources, ~60 MB on average.

using wrapper llvm::sort(nfc)

These are identified by misc-include-cleaner.  I've filtered out those
that break builds.  Also, I'm staying away from llvm-config.h,
config.h, and Compiler.h, which likely cause platform- or
compiler-specific build failures.

This reverts commit aa9f8596b01fef013ab62c20e61fc96d165f60f7 because it made
some assumptions that may not be valid.

FullLTO has to run this early before module splitting occurs otherwise
module splitting won't work as expected. There was a targeted fix for
fortran on another branch that disables the LTO run but that'd break
full LTO module splitting entirely.

Test changes are due to metadata indexes shifting.

See #122891