[Coverity][UR] Potential double-unlock of a mutex in the L0 adapter

[AlexeySachkov]

Reported by Coverity as CID 520793, you can access Coverity results here: https://scan.coverity.com/projects/intel-llvm?tab=overview

The following piece of code:

llvm/unified-runtime/source/adapters/level_zero/event.cpp

Lines 1585 to 1588 in faa6180

	if (Queue && Queue != CurQueue) {
	CurQueue->Mutex.unlock();
	QueueLock = std::unique_lock<ur_shared_mutex>(Queue->Mutex);
	}

Is located within a loop:

llvm/unified-runtime/source/adapters/level_zero/event.cpp

Lines 1552 to 1553 in faa6180

	for (uint32_t I = 0; I < EventListLength; I++) {
	{

Meaning, that we may call CurQueue->Mutex.unlock(); multiple times. That mutex is a std::shared_mutex whose unlock method behavior is undefined if a mutex is already unlocked.