translator: Refactor interface block layout qualifiers.
translator: Refactor interface block layout qualifiers.

This will make it easier to insert internal uniform layouts in Vulkan.

Bug: angleproject:2717
Change-Id: Ic1a76848337cc67a57698913c584d8596bf4f27e
Reviewed-on: https://chromium-review.googlesource.com/1127300
Reviewed-by: Geoff Lang <b6fc25fe0362055230985c05cbfa8adb741ccc0f@chromium.org>
Reviewed-by: Luc Ferron <a2389c1bcb3ee32b089866e04e35d1a302020674@chromium.org>
Commit-Queue: Jamie Madill <7e492b4f1c8458024932de3ba475cbf015424c30@chromium.org>

ppy/angle,ppy/angle,ppy/angle,ppy/angle