[cmake] Unconditionally use -Wno-pass-failed with Clang (#162835)

Since 4feae05c6abda364a9295aecfa600d7d4e7dfeb6, most of the handling of
warning options was rewritten to add such options based on hardcoded
knowledge about what compilers support which options, and since which
versions. This avoids a number of configure time checks, speeding up the
cmake configuration.

This avoids erroneously adding this option with GCC, which doesn't
really support it.

If testing for a warning option like -Wno-<foo> with GCC, GCC won't
print any diagnostic at all, leading to the options being accepted
incorrectly. However later, if compiling a file that actually prints
another warning, GCC will also print warnings about these -Wno-<foo>
options being unrecognized.

This avoids extra warning spam like this, for every source file that
does produce warnings with GCC:

    At global scope:
    cc1plus: note: unrecognized command-line option ‘-Wno-pass-failed’ may have been intended to silence earlier diagnostics

0 files changed, 0 insertions, 0 deletions