[clang] [runtimes] Fix parsing of LIB{CXX, CXXABI, UNWIND}_TEST_PARAMS (PR #67691)

[Alexander Richardson via cfe-commits]

arichardson wrote:

> @ldionne @arichardson , the problem is still there for more than 10 days already. Do you guys plan to fix it!

I am waiting for @ldionne to approve this PR.

https://github.com/llvm/llvm-project/pull/67691