perf python: Remove -fstack-clash-protection when building with some clang versions

perf python: Remove -fstack-clash-protection when building with some clang versions

These options are not present in some (all?) clang versions, so when we
build for a distro that has a gcc new enough to have these options and
that the distro python build config settings use them but clang doesn't
support, b00m.

This is the case with fedora rawhide (now gearing towards f30), so check
if clang has the  and remove the missing ones from CFLAGS.

Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Thiago Macieira <thiago.macieira@intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-5q50q9w458yawgxf9ez54jbp@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>