[compiler-rt] [compiler-rt][ARM] Optimized mulsf3 and divsf3 (PR #161546)

[Simon Tatham via llvm-commits]

statham-arm wrote:

I had to revert this immediately because of a buildbot breakage. I didn't understand it at the time, because the error message was confusing, but now I do understand.

The new `check_assembler_flag` cmake function uses `try_compile` in a mode where it tries to compile a single source file rather than a whole project. But that mode of `try_compile` was introduced in cmake 3.25, and LLVM only enforces 3.20 or better. The Fuchsia buildbot is running on Ubuntu 22.04, which has 3.22.1.

https://github.com/llvm/llvm-project/pull/161546