- Revert r372777: [libc++] Implement LWG 2510 and its follow-ups This also reverts: - r372778: [libc++] Implement LWG 3158 - r372782: [libc++] Try fixing tests that fail on GCC 5 and older - r372787: Purge mentions of GCC 4 from the test suite Reason: the change breaks compilation of LLVM with libc++, for details see http://lists.llvm.org/pipermail/libcxx-dev/2019-September/000599.html
- Add tracing in pickNodeFromQueue. This matches GenericScheduler::pickNodeFromQueue, from which this function was mostly cut and pasted.
- Fix signature of overloaded operator delete. This overload was left over from an operator new that was removed in r123027. Fix it to match another operator new that was added in r248453.