[llvm] Use thinlto and pgo for x86_64 windows release packaging (PR #71067)

[via llvm-commits]

ms178 wrote:

> > Why stop with LTO+PGO? BOLTing Clang/LLD should yield another sizeable improvement.
> 
> My understanding was the BOLT for PE/COFF binaries isn't production ready.

@maksfb or @aaupov might have some insights to share about PE/COEFF binary support of BOLT or might be interested in a BOLT-optimized Windows release package.

https://github.com/llvm/llvm-project/pull/71067