Shader translator changes done in http://crrev.com/c/2633936

Adds a new DIRTY_BIT_PATCH_VERTICES state to Context.
Supportes state query and transform feedback.
4 test suppressions remain as follow-up fixes.
Adds a new varying packing mode for a simple Vulkan rule set.

Based on work by Mohan Maiya (m.maiya@samsung.com).

Test: dEQP-GLES31.functional.tessellation.*
Bug: angleproject:3572
Change-Id: I4cad2cca30adb754fd12c83027673906541f566a
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2568234Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Mohan Maiya <m.maiya@samsung.com>
Commit-Queue: Jamie Madill <jmadill@chromium.org>