Make JS runtime only used in the creator thread.
Because the SpiderMoneky use thread-local storage.
Make JS data dispose in the runtime creator thread.
See https://github.com/ricardoquesada/Spidermonkey/blob/master/mfbt/ThreadLocal.h
and https://github.com/ricardoquesada/Spidermonkey/blob/abb95806397d0a3523263a1faf5b21923b35f508/js/src/vm/Runtime.cpp