Switch how destroyHardwareResources works

destroyHardwareResources will now only force-destroy
the specific node it was called on, which are only
ever the root nodes. Rely on onRemovedFromTree()
to clean up resources for all other nodes.

Bug: 34736819

Test: RenderNode.multiTreeValidity passes, manually
verified fixes b/34736819

Change-Id: I1c275ad6a98b63bf50f265602f09bffe3e1f169b