perf test: Add test cases for new data source encoding

Add some simple tests to perf test to test data source printing.

v2: Make the tests actually checked for the correct name of Forward
v3: Adjust to new encoding

Committer notes:

Avoid the in place declaration to make this build with older compilers,
for instance, in Debian 7 we get:

  tests/mem.c: In function 'test__mem':
  tests/mem.c:30:5: error: missing initializer [-Werror=missing-field-initializers]
  tests/mem.c:30:5: error: (near initialization for '(anonymous).<anonymous>.mem_snoop') [-Werror=missing-field-initializers]

So just zero a struct, then go on building the unions as needed,
reusing settings from the previous test, i.e. local -> remote, etc.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Link: http://lkml.kernel.org/r/20170816222156.19953-5-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/tests/builtin-test.c b/tools/perf/tests/builtin-test.c
index 9ecc44e..377bea0 100644
--- a/tools/perf/tests/builtin-test.c
+++ b/tools/perf/tests/builtin-test.c
@@ -48,6 +48,10 @@ static struct test generic_tests[] = {
 		.func = test__basic_mmap,
 	},
 	{
+		.desc = "Test data source output",
+		.func = test__mem,
+	},
+	{
 		.desc = "Parse event definition strings",
 		.func = test__parse_events,
 	},