tools/perf/build: Speed up auto-detection of features by adding a 'test-all' target

Concatenate all feature checks into test-all.c.

This can be built and checked faster than all the individual tests.

If test-all fails then we still check all the individual features, so
this is a pure speedup, it should have no effects on functionality.

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-5hlcb2qorzwfwrWTjiygjjih@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>