Roll src/third_party/swiftshader 59a29e3c4f03..8e8e1d0dd729 (2 commits)

https://swiftshader.googlesource.com/SwiftShader.git/+log/59a29e3c4f03..8e8e1d0dd729

git log 59a29e3c4f03..8e8e1d0dd729 --date=short --first-parent --format='%ad %ae %s'
2020-02-04 bclayton@google.com Shader: Add missing switch cases to operationString
2020-02-04 bclayton@google.com OpenGL: Fix switch with only a default case.

Created with:
  gclient setdep -r src/third_party/swiftshader@8e8e1d0dd729

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/swiftshader-chromium-autoroll
Please CC swiftshader-team+autoroll@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: luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_chromium_msan_rel_ng;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel
Bug: None
Tbr: swiftshader-team+autoroll@google.com
Change-Id: If91d956eb882e7d7b5f9d1ef6109fcb0e426b155
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2037626Reviewed-by: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Commit-Queue: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#738449}

DEPS

@@ -192,7 +192,7 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling SwiftShader
   # and whatever else without interference from each other.
-  'swiftshader_revision': '59a29e3c4f030bc4a835a8cb8ebdefaa1f58b74d',
+  'swiftshader_revision': '8e8e1d0dd7292440b803b95bc0832589520f784d',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling PDFium
   # and whatever else without interference from each other.