[libc][cmake] Suppress -Wpsabi note on GCC and clean up resource-dir check. (#227968)

- Add `-Wno-psabi` to GCC compile options to suppress ABI change notes
for 80-bit long double unions.
- Pass `ERROR_QUIET` to clang-specific `--print-resource-dir` query in
`libc/CMakeLists.txt` so it does not output errors on GCC and MSVC.

Assisted-by: Gemini
GitOrigin-RevId: 9a891dfc2c17fda49accc8c37cf4c2ddde6fa7d7