This will enable accurate XFB primitive counts when using tessellation
and geometry shaders. Adds new vk::QueryResult and gl::QueryTypeMap
helper classes.

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

Bug: angleproject:3572
Change-Id: Ie3f496deda887c13bb4ad7ab430e31d615849bfd
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2564002
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Mohan Maiya <m.maiya@samsung.com>