[clang] [Driver] Ensure ToolChain::LibraryPaths is not empty for non-Darwin (PR #87866)

[Arthur Eubanks via cfe-commits]

aeubanks wrote:

it seems that the test depends on if certain android runtime libraries are present or not in the resource dir (without per-target runtime directory since that's still an issue on Android). perhaps the tests need `-resource-dir` to make them more hermetic?

anyway, will revert, feel free to reland once the tests are fixed. this is what's in my resource dir if it's helpful for reproducing

```
$ ls lib/clang/19/lib/linux/
aarch64                              libclang_rt.asan_cxx-aarch64-android.a      libclang_rt.builtins-aarch64-android.a  libclang_rt.tsan_cxx-aarch64-android.a          libclang_rt.ubsan_standalone-aarch64-android.so
libclang_rt.asan-aarch64-android.a   libclang_rt.asan-preinit-aarch64-android.a  libclang_rt.profile-aarch64-android.a   libclang_rt.ubsan_minimal-aarch64-android.a     libclang_rt.ubsan_standalone_cxx-aarch64-android.a
libclang_rt.asan-aarch64-android.so  libclang_rt.asan_static-aarch64-android.a   libclang_rt.tsan-aarch64-android.a      libclang_rt.ubsan_standalone-aarch64-android.a
```

https://github.com/llvm/llvm-project/pull/87866