Roll third_party/externals/swiftshader cf1866183620..2e96bac879cf (2 commits)

https://swiftshader.googlesource.com/SwiftShader.git/+log/cf1866183620..2e96bac879cf


git log cf1866183620..2e96bac879cf --date=short --no-merges --format='%ad %ae %s'
2019-03-22 bclayton@google.com Regres: Transition from out/ to build/
2019-03-22 bclayton@google.com Regres: Include an example test for each of top N failures


Created with:
  gclient setdep -r third_party/externals/swiftshader@2e96bac879cf

The AutoRoll server is located here: https://autoroll.skia.org/r/swiftshader-skia-autoroll

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

If the roll is causing failures, please contact the current sheriff, who should
be CC'd on the roll, and stop the roller if necessary.

CQ_INCLUDE_TRYBOTS=skia.primary:Test-Debian9-Clang-GCE-GPU-SwiftShader-x86_64-Debug-All-SwiftShader
TBR=brianosman@google.com

Change-Id: Ia42b6c28697ac3aabeb57fb8e721ba4f5284f9c8
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/203061
Reviewed-by: skia-autoroll <skia-autoroll@skia-public.iam.gserviceaccount.com>
Commit-Queue: skia-autoroll <skia-autoroll@skia-public.iam.gserviceaccount.com>