[llvm] [LoopDist] Add metadata for checking post process state of distribute… (PR #153902)

[Michael Kruse via llvm-commits]

https://github.com/Meinersbur commented:

Why a count instead of just a flag that marks the loop as already vectorized? `.count` looks like an instruction to the compiler to distribute into that number of os parts (compate `llvm.loop.unroll.count`).

LoopVectorizer's marker is `llvm.loop.isvectorized`. 

https://github.com/llvm/llvm-project/pull/153902