Fixes two issue for build Vulkan backend for android ndk level < 26, * Disable Vulkan validation layers for android ndk level < 26 * Share vulkan memory allocator implementation with chrome to avoid duplicated symbols link errors. * Only run vulkan backend test with Android P or newer Note: This change will break android-binary-size try bot, we need to update expected_static_initializer_count to 4 at [1] while rolling this change into chromium. [1] https://source.chromium.org/chromium/chromium/src/+/master:chrome/android/static_initializers.gni;l=19?q=expected_static_initializer_count&ss=chromium%2Fchromium%2Fsrc Bug: chromium:1170339 Change-Id: Idb9238d8f339724c4d8f9ac136305b95ff06fae4 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2656980 Commit-Queue: Peng Huang <penghuang@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org>
