Enable VK_EXT_global_priority

This extension is used to set context priority for Vulkan
queues. Without it, Properties::contextPriority is ignored.

Bug: 290104871
Test: Chrome swipe home
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:e545f96ec6a1d0da6359a042d3c7f0c701e451f9)
Merged-In: I362f0f253b466cfcbcebbe79936ae9a5c5261d92
Change-Id: I362f0f253b466cfcbcebbe79936ae9a5c5261d92