Revert "Abolish absClear"

This reverts commit f948db6228fd8dce2ba2a6ff2dfec53ff95d3f90.

Reason for revert: Vulkan assertion on Nexus5

Original change's description:
> Abolish absClear
> 
> Bug: skia:
> Change-Id: Ic4a0e640623677c06112d0735ffc5682049baf11
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/240771
> Commit-Queue: Chris Dalton <csmartdalton@google.com>
> Reviewed-by: Michael Ludwig <michaelludwig@google.com>

TBR=egdaniel@google.com,bsalomon@google.com,robertphillips@google.com,csmartdalton@google.com,michaelludwig@google.com

Change-Id: I071c9878d26ce0f1d91473ada48e9a702bb472de
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: skia:
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/242480
Reviewed-by: Chris Dalton <csmartdalton@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>
4 files changed