Support for layout qualifiers in interface blocks are added.  All
interface blocks are adjusted to either be in std140 or std430.

In the Vulkan backend, a new descriptor set is added for UBOs.  A dirty
bit is added for UBO updating and pipeline layouts and descriptor
bindings are updated.

Bug: angleproject:3199, angleproject:3220
Change-Id: I271fc34ac2e1e8b76dee75e54a7cff0fe15fe4ee
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1565061
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>