util/gitconfig: Add timeout test

Add a `util/gitconfig/test` subdirectory which will contain tests to run
as executable files, add a helper script.

Add a timeout test that verifies that gitconfig completes in under two
seconds (typical run time is ~30 ms). Add gitconfig tests to the
`testing` Makefile under the `test-tools` target.

Change-Id: Id46f905b9f782e67be97a65d10045c3345dc996b
Signed-off-by: Alex Thiessen <alex.thiessen.de+coreboot@gmail.com>
Reviewed-on: https://review.coreboot.org/23280
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

util/testing/Makefile.inc

@@ -123,6 +123,12 @@ test-tools:
 	$(MAKE) -C util/romcc all test -j $(CPUS) V=$(V) Q=$(Q)
 	echo "Testing broadcom/secimage"
 	$(MAKE) -C util/broadcom/secimage test
+	@echo "Running gitconfig tests"
+	@for test in $$(find util/gitconfig/test -maxdepth 1 \
+		-type f -executable); do \
+		echo "$${test}"; \
+		"$${test}" || exit $${?}; \
+	done
 
 test-cleanup:
 	rm -rf coreboot-builds coreboot-builds-chromeos