This reverts commit 983e4469.

Reason for revert: Depends on a CL that's reverted: https://chromium-review.googlesource.com/c/angle/angle/+/1470605

Original change's description:
> Vulkan: Implement debug markers
> 
> Covers both GL_KHR_debug and GL_EXT_debug_marker.
> 
> Debug markers are used to specify events or hierarchically categorize a
> set of commands within the command buffer.  When debugging, this allows
> for quicker navigation to the draw calls of interest, and otherwise
> provides context to debug output.
> 
> Bug: angleproject:2853
> Change-Id: Id65e11fc877d9e70b6fd0fae7f0bbbcb1164bf10
> Reviewed-on: https://chromium-review.googlesource.com/c/1403956
> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
> Reviewed-by: Jamie Madill <jmadill@chromium.org>
> Reviewed-by: Geoff Lang <geofflang@chromium.org>

TBR=geofflang@chromium.org,jmadill@chromium.org,syoussefi@chromium.org

Change-Id: I7fcfc8683195d396aec61848719f52c0fa049ece
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: angleproject:2853
Reviewed-on: https://chromium-review.googlesource.com/c/1470606Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>