Fix memory leak in deferred a11y dispatcher. DO NOT MERGE

This CL fixes a memory leak in RV where if it had some pending a11y
changes to dispatch, it would potentially leak the view holders if
any of them is removed (which is fairly common).

Bug: 32986945
Test: RecyclerViewAccessibilityLifecycleTest#processAllViewHolders
Change-Id: I4f3246970153d1616ad8e653b1f9653253ba9bcb
2 files changed