test: stop the compat server even when startup fails

test-with-server depended on start-server as a prerequisite, so a failed
startup skipped the recipe and the spawned weed mini kept the port.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

test/s3/error_compat/Makefile

@@ -89,8 +89,9 @@ test-errors:
 		--access-key admin \
 		--secret-key admin
 
-test-with-server: start-server
-	@$(MAKE) test-errors; TEST_RESULT=$$?; \
+test-with-server:
+	@$(MAKE) start-server; START_RESULT=$$?; \
+	if [ $$START_RESULT -eq 0 ]; then $(MAKE) test-errors; TEST_RESULT=$$?; else TEST_RESULT=$$START_RESULT; fi; \
 	$(MAKE) stop-server; exit $$TEST_RESULT
 
 logs: