Vulkan: Resolve GoogleX MSRTSS conflict with EXT Now that the extension is public, rename the old symbols to GoogleX as they have shipped previously. This reverts defd99dc4. Bug: chromium:1088005 Change-Id: I5ac7f73e24084e26a8b2d9cf742c7ab9b3c80984 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3744362 Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Ian Elliott <ianelliott@google.com>