Revert "Fix a race when dumping thread list for tracing"

This reverts commit bd10861f33fcc1a1e7ddae3c48eb452a398e74a4.

Reason for revert: Breaks few builds:
https://ci.chromium.org/ui/p/art/builders/ci/host-x86-poison-debug/7874/overview

Change-Id: If82aa3c2f66396cdc08cf95a841ef90ac36bc201
5 files changed