libperf: Change tests to single static and shared binaries

Make tests to be two binaries 'tests_static' and 'tests_shared', so the
maintenance is easier.

Adding tests under libperf build system, so we define all the flags just
once.

Adding make-tests tule to just compile tests without running them.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Shunsuke Nakamura <nakamura.shun@fujitsu.com>
Link: http://lore.kernel.org/lkml/20210706151704.73662-2-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/lib/perf/include/internal/tests.h

@@ -5,8 +5,8 @@
 #include <stdio.h>
 #include <unistd.h>
 
-int tests_failed;
-int tests_verbose;
+extern int tests_failed;
+extern int tests_verbose;
 
 static inline int get_verbose(char **argv, int argc)
 {