[compiler-rt] [test][compiler-rt] Mark several tests as UNSUPPORTED on LoongArch (PR #69699)

[Lu Weining via llvm-commits]

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

LGTM for now so that we can turn on compiler-rt testing on buildbot. And let's remove these `UNSUPPORTED` flags when we support.

https://github.com/llvm/llvm-project/pull/69699