Remove unknown test flag

Makefile

@@ -3,7 +3,7 @@ CARGO_CMD ?= cargo
 packages = bigint integer rational traits
 
 test:
-	$(MAKE) run-all TASK="test --no-fail-fast"
+	$(MAKE) run-all TASK="test"
 
 run-all: $(packages)
 	$(CARGO_CMD) $(TASK)