Re-land "Vulkan: Add glslang validator to build."
Re-land "Vulkan: Add glslang validator to build."

This binary will be used to generate internal shaders for
clearing/blit/etc.

Re-land fixes missing GN dependencies.

Bug: angleproject:2339
Change-Id: I99a966906f6cd31049807b7b7adf39484c951622
Reviewed-on: https://chromium-review.googlesource.com/924177
Commit-Queue: Jamie Madill <7e492b4f1c8458024932de3ba475cbf015424c30@chromium.org>
Reviewed-by: Luc Ferron <a2389c1bcb3ee32b089866e04e35d1a302020674@chromium.org>

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