Acquire qpmulti->mutex during destruction

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.