Vulkan: Make CommandProcessor use ThreadSafeCommandQueue This CL switches CommandProcessor's mCommandQueue to ThreadSafeCommandQueue. This allows us to utilize ThreadSafeCommandQueue implementation of wait for GPU to finish while CommandProcessor's async submission thread continue to submit. By doing this, CommandQueue is only used by ThreadSafeCommandQueue, thus some public APIs can now removed. This CL also implements wait APIs of ThreadSafeCommandProcessor directly and remove these APIs from CommandProcessor class. Bug: b/261106868 Change-Id: I8c2e1de95a37fab21b7018db484976c447f1dcad Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/4163743 Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Commit-Queue: Charlie Lao <cclao@google.com> Reviewed-by: Amirali Abdolrashidi <abdolrashidi@google.com>