[clang] [llvm] Reland: [llvm][clang] Allocate a new stack instead of spawning a new thread to get more stack space (PR #136046)

[Reid Kleckner via cfe-commits]

https://github.com/rnk approved this pull request.

If we ever generalize this, it would make sense to have a standalone .s /.asm file in the build.

https://github.com/llvm/llvm-project/pull/136046