[compiler-rt] CompilerRT: Normalize COMPILER_RT_DEFAULT_TARGET_TRIPLE (PR #88835)

[YunQiang Su via llvm-commits]

wzssyqa wrote:

The previous PR introduced 2 test fails:
     https://lab.llvm.org/buildbot/#/builders/98/builds/36366
Should be resolved by 1693009679313282afbed38778dd3fad62641e1b


https://lab.llvm.org/buildbot/#/builders/77/builds/36372
due to the previous patch overwrite the var `COMPILER_RT_DEFAULT_TARGET_TRIPLE`.
It has been fixed in this version.

https://github.com/llvm/llvm-project/pull/88835