Vulkan: Move RefCountedEvent GC and recycler to ShareGroupVk (3/3) With previous CLs, RefCountedEvents are increment/decrement only within contexts in the same ShareGroup, thus we no longer needs atomic operation. This CL switchs RefCountedEvent to use RefCounted instead of AtomicRefCounted. Bug: b/336844257 Change-Id: Ic5aa9b0f28b8f817f820f595d3de945ce37dbd0e Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5527617 Reviewed-by: Amirali Abdolrashidi <abdolrashidi@google.com> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Charlie Lao <cclao@google.com> Commit-Queue: Charlie Lao <cclao@google.com>