Vulkan: Handle extension enumeration returning less than requested Speculative fix for b/249457381 where we have previously seen extensions enabled/disabled based on settings which may be loaded/changed between vkEnumerate*() calls. Bug: b/249457381 Change-Id: I36aa8aec38037ff3d8c9a036d27289e1abb930fb Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/4006713 Reviewed-by: Ian Elliott <ianelliott@google.com> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>