Fix run_node_tests exit code
Fix run_node_tests exit code

In node, quit() is process.exit(). Annoyingly, exceptions in dangling promises
fail silently in Node, so this error wasn't obvious until I started looking at
exit codes.

TBR=nednguyen
BUG=catapult:#1991

Review URL: https://codereview.chromium.org/1681323002

sahiljain/catapult,sahiljain/catapult,SummerLW/Perf-Insight-Report,catapult-project/catapult,catapult-project/catapult-csm,SummerLW/Perf-Insight-Report,benschmaus/catapult,sahiljain/catapult,benschmaus/catapult,benschmaus/catapult,benschmaus/catapult,catapult-project/catapult,sahiljain/catapult,catapult-project/catapult,benschmaus/catapult,sahiljain/catapult,SummerLW/Perf-Insight-Report,benschmaus/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult-csm,sahiljain/catapult,catapult-project/catapult-csm,SummerLW/Perf-Insight-Report,catapult-project/catapult-csm,catapult-project/catapult-csm,catapult-project/catapult-csm,SummerLW/Perf-Insight-Report,catapult-project/catapult,SummerLW/Perf-Insight-Report,catapult-project/catapult,benschmaus/catapult,catapult-project/catapult-csm