Roll third_party/externals/swiftshader 5cf1e9a31c90..cb58662302c8 (7 commits)
Roll third_party/externals/swiftshader 5cf1e9a31c90..cb58662302c8 (7 commits)

https://swiftshader.googlesource.com/SwiftShader.git/+log/5cf1e9a31c90..cb58662302c8

git log 5cf1e9a31c90..cb58662302c8 --date=short --first-parent --format='%ad %ae %s'
2020-04-01 cwallez@cwallez-macbookpro3.roam.corp.google.com MetalSurface: set layer.device to a ref of the system default device.
2020-04-01 bclayton@google.com Regres: Add invertCommon optimization.
2020-04-01 bclayton@google.com Regres: Move optimization logic to separate file
2020-04-01 bclayton@google.com Regres: Keep coverage span groups stable.
2020-04-01 bclayton@google.com Regres: Split coverage.go into multiple files
2020-04-01 bclayton@google.com Regres: Further optimizations for coverage
2020-04-01 bclayton@google.com Regres: Add cov.ReadJSON()

Created with:
  gclient setdep -r third_party/externals/swiftshader@cb58662302c8

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/swiftshader-skia-autoroll
Please CC cb1f3dd24de0f0b611b26bc28bec758a551d9b7d@google.com on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

Cq-Include-Trybots: skia/skia.primary:Test-Debian9-Clang-GCE-GPU-SwiftShader-x86_64-Debug-All-SwiftShader
Bug: None
Tbr: cb1f3dd24de0f0b611b26bc28bec758a551d9b7d@google.com
Change-Id: I6971ae0214b4f6a29cc562363884a64825919be2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/281091
Reviewed-by: skia-autoroll <e034c62197df5622a9c1bef8b3e012f87a0a9840@skia-public.iam.gserviceaccount.com>
Commit-Queue: skia-autoroll <e034c62197df5622a9c1bef8b3e012f87a0a9840@skia-public.iam.gserviceaccount.com>

aosp-mirror/platform_external_skia,google/skia,google/skia,google/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,google/skia,aosp-mirror/platform_external_skia,google/skia,google/skia,google/skia,google/skia,aosp-mirror/platform_external_skia,google/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,google/skia