tests: Improve test output readability

When running multiple tests, e.g. by using unit-tests target, it is hard
to differentiate, which output comes from which file and/or
configuration. This patch makes the output easier to analyze and
understand by using new wrapper macro cb_run_group_tests(). This macro
uses __TEST_NAME__ value (containing test path and Makefile test name)
as a group name when calling cmocka group runner.

Example:
 Test path: tests/lib/
 Makefile test name: cbmem_stage_cache-test
 Test group array name: tests
 Result: tests/lib/cbmem_stage_cache-test(tests)

Signed-off-by: Jakub Czapiga <jacz@semihalf.com>
Change-Id: I4fd936d00d77cbe2637b857ba03b4a208428ea0d
Reviewed-on: https://review.coreboot.org/c/coreboot/+/57144
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Fagerburg <pfagerburg@chromium.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>

tests/device/ddr4-test.c

@@ -37,5 +37,5 @@ int main(void)
 		cmocka_unit_test(ddr4_speed_mhz_to_mts_test)
 	};
 
-	return cmocka_run_group_tests(tests, NULL, NULL);
+	return cb_run_group_tests(tests, NULL, NULL);
 }