Acquire qpmulti->mutex during destruction
Thread sanitizer warns that parts of the qp-trie are accessed both with and without the mutex; the unlocked accesses happen during destruction, so they should be benign, but there's no harm locking anyway to convince tsan it is clean.
Also, ensure .tsan-suppress and .tsan-suppress-extra are in sync.
Closes #4070 (closed) and #4073 (closed)