libperf: Add perf_thread_map test

Add simple perf_thread_map tests.

Committer testing:

  $ make O=/tmp/build/perf -C tools/perf/lib tests
  make: Entering directory '/home/acme/git/perf/tools/perf/lib'
    LINK     test-cpumap-a
    LINK     test-threadmap-a
    LINK     test-cpumap-so
    LINK     test-threadmap-so
  running static:
  - running test-cpumap.c...OK
  - running test-threadmap.c...OK
  running dynamic:
  - running test-cpumap.c...OK
  - running test-threadmap.c...OK
  make: Leaving directory '/home/acme/git/perf/tools/perf/lib'
  $
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20190721112506.12306-75-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/lib/tests/Makefile

 # SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
 
-TESTS = test-cpumap
+TESTS = test-cpumap test-threadmap
 
 TESTS_SO := $(addsuffix -so,$(TESTS))
 TESTS_A  := $(addsuffix -a,$(TESTS))

tools/perf/lib/tests/test-threadmap.c

+// SPDX-License-Identifier: GPL-2.0
+#include <perf/threadmap.h>
+#include <internal/tests.h>
+
+int main(int argc, char **argv)
+{
+	struct perf_thread_map *threads;
+
+	__T_START;
+
+	threads = perf_thread_map__new_dummy();
+	if (!threads)
+		return -1;
+
+	perf_thread_map__get(threads);
+	perf_thread_map__put(threads);
+	perf_thread_map__put(threads);
+
+	__T_OK;
+	return 0;
+}