Roll src/third_party/swiftshader 9418b511c73b..094974dab674 (3 commits)

https://swiftshader.googlesource.com/SwiftShader.git/+log/9418b511c73b..094974dab674

git log 9418b511c73b..094974dab674 --date=short --first-parent --format='%ad %ae %s'
2020-04-15 bclayton@google.com VkPipelineCache: Do not publically expose internal mutexes
2020-04-15 bclayton@google.com CMake: Fix build when building with `SWIFTSHADER_ENABLE_VULKAN_DEBUGGER`
2020-04-15 sugoi@google.com Fix fragments depth values not being clamped

Created with:
  gclient setdep -r src/third_party/swiftshader@094974dab674

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;luci.chromium.try:linux-swangle-try-x64;luci.chromium.try:win-swangle-try-x86
Bug: None
Tbr: swiftshader-team+autoroll@google.com
Change-Id: I5f72e5669020ef9745a19fc465bd6e2c000a00a8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2150417Reviewed-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@{#759243}

DEPS

@@ -191,7 +191,7 @@ 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': '9418b511c73bc2b079d8b8d8d6fcb5d40b814159',
+  'swiftshader_revision': '094974dab6741749fd9cf4fce4fa04d323678610',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling PDFium
   # and whatever else without interference from each other.