For testing. This reduces memory needed for JIT test. The -f flag will print
the full patch of failures (want to keep this).
In-house patch for testing.

diff --git a/js/src/Makefile.in b/js/src/Makefile.in
--- a/js/src/Makefile.in
+++ b/js/src/Makefile.in
@@ -101,7 +101,7 @@
 
 check-jit-test::
 	$(JITTEST_SANITIZER_ENV) $(wildcard $(RUN_TEST_PROGRAM)) $(PYTHON) -u $(srcdir)/jit-test/jit_test.py \
-	        --no-slow --no-progress --format=automation --jitflags=all \
+	        --no-slow --no-progress --format=automation --jitflags=all -j 2 -f \
 			$(JITTEST_VALGRIND_FLAG) \
 			$(JITTEST_EXTRA_ARGS) \
 	        $(DIST)/bin/$(JS_SHELL_NAME)$(BIN_SUFFIX) $(JITTEST_TEST_ARGS)