Make sure we check the version number of Vulkan Extensions.

Bug: skia:
Change-Id: Iff02911491cc61e39f94370c644b6666e5f9118f
Reviewed-on: https://skia-review.googlesource.com/137881
Commit-Queue: Greg Daniel <egdaniel@google.com>
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
12 files changed