Fix a race condition when tearing down FrameInfo (#9413)

* HandleAllocator::deallocate() was unsafe

It needs to know the concrete type to call the proper destructor, so
if it was given a base type handle (e.g. Handle<HwFoo>) it would not
destroy it properly.

* add AsyncJobQueue::cancelAll()

* Fix a race condition when tearing down FrameInfo

It is actually invalid to destroy a Handle<HwFence> while inside
fenceWait().

Updated the HwFence implementations so that they don't pretend they can
handle being destroyed during fenceWait(), they can't.

FrameInfo now cancels all the pending callbacks and waits for the 
currently executing one to terminate, *before* destroying the
handles.

Reenable the gpuFrameComplete metric, as it should be working now.

libs/utils/src/AsyncJobQueue.cpp

@@ -60,6 +60,13 @@ AsyncJobQueue::~AsyncJobQueue() noexcept {
 #endif
 }
 
+void AsyncJobQueue::cancelAll() noexcept {
+#if !defined(__EMSCRIPTEN__)
+    std::unique_lock const lock(mLock);
+    mQueue.clear();
+#endif
+}
+
 void AsyncJobQueue::push(Job&& job) {
 #if !defined(__EMSCRIPTEN__)
     std::unique_lock lock(mLock);