[libcxx] [libcxxabi] [libunwind] [libc++/libc++abi/libunwind] Add new test configs for Clang runtime library. NFC. (PR #82734)

[Vladimir Vereschaka via cfe-commits]

vvereschaka wrote:

@ldionne , would take a quick look? These test configurations are based on the default llvm test configurations for the static libraries, but just added `clang_rt` library into the linker's command line.
Thanks.

https://github.com/llvm/llvm-project/pull/82734