[clang] clang/win: Add a flag to disable default-linking of compiler-rt libraries (PR #89642)

[Nico Weber via cfe-commits]

nico wrote:

Good call-out, thanks. I meant #87866, which is new.

I also forgot that llvm-project likes to do squash commits and put the new commit message in the old commit and `git push -f`'d. But the only thing that changed in the new commit is the commit message text.

https://github.com/llvm/llvm-project/pull/89642