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/Makefile.inc

@@ -136,7 +136,8 @@ $$($(1)-config-file): $(TEST_KCONFIG_AUTOHEADER)
 	printf '#endif\n' >> $$@;
 
 $($(1)-objs): TEST_CFLAGS += -I$$(dir $$($(1)-config-file)) \
-	-D__$$(shell echo $$($(1)-stage) | tr '[:lower:]' '[:upper:]')__
+	-D__$$(shell echo $$($(1)-stage) | tr '[:lower:]' '[:upper:]')__ \
+	-D__TEST_NAME__=\"$(1)\"
 
 # Give us a way to distinguish between coreboot source files and test files in code.
 $($(1)-srcobjs): TEST_CFLAGS += -D__TEST_SRCOBJ__