Firefox really, finally, actually fixed

Matt Dillon and Venkatesh Srinivas conspired to fix another nmalloc issue, which should resolve any remaining problems people were having with Firefox, and possibly other applications as well. Due to an oversight of sorts, all locking operations on nmalloc’s depot were ineffective, as if there were no locking at all. Curiously, it worked remarkably well considering such a large race condition was present.