Roll third_party/externals/swiftshader 74d3f371f201..f50cc82b3bed (6 commits)

https://swiftshader.googlesource.com/SwiftShader.git/+log/74d3f371f201..f50cc82b3bed

git log 74d3f371f201..f50cc82b3bed --date=short --first-parent --format='%ad %ae %s'
2020-02-20 [email protected] Subzero: add support for large stacks on Windows
2020-02-20 [email protected] VK_EXT_shader_stencil_export support
2020-02-20 [email protected] Remove rr::Thread
2020-02-20 [email protected] Support JIT on a separate thread
2020-02-20 [email protected] Revert "VK_EXT_shader_stencil_export support"
2020-02-20 [email protected] VK_EXT_shader_stencil_export support

Created with:
  gclient setdep -r third_party/externals/swiftshader@f50cc82b3bed

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 [email protected] 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: [email protected]
Change-Id: I9a65247e81025da8eee04829b9738e044eaac100
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/272544
Reviewed-by: skia-autoroll <[email protected]>
Commit-Queue: skia-autoroll <[email protected]>

Author: skia-autoroll

DEPS

@@ -31,7 +31,7 @@ deps = {
   "third_party/externals/spirv-cross"     : "https://chromium.googlesource.com/external/github.com/KhronosGroup/SPIRV-Cross@dffd33dd9d19c798ffecc10f50e551b42d282628",
   "third_party/externals/spirv-headers"   : "https://skia.googlesource.com/external/github.com/KhronosGroup/SPIRV-Headers.git@29c11140baaf9f7fdaa39a583672c556bf1795a1",
   "third_party/externals/spirv-tools"     : "https://skia.googlesource.com/external/github.com/KhronosGroup/SPIRV-Tools.git@0c4feb643b89d1792b02f7cbef315e9d95633bd7",
-  "third_party/externals/swiftshader"     : "https://swiftshader.googlesource.com/SwiftShader@74d3f371f2015deeedb985a8b24ba242ea65caef",
+  "third_party/externals/swiftshader"     : "https://swiftshader.googlesource.com/SwiftShader@f50cc82b3bed049f50ce8e530e3be5db307baa64",
   #"third_party/externals/v8"              : "https://chromium.googlesource.com/v8/v8.git@5f1ae66d5634e43563b2d25ea652dfb94c31a3b4",
   "third_party/externals/wuffs"           : "https://skia.googlesource.com/external/github.com/google/wuffs.git@4080840928c0b05a80cda0d14ac2e2615f679f1a",
   "third_party/externals/zlib"            : "https://chromium.googlesource.com/chromium/src/third_party/zlib@47af7c547f8551bd25424e56354a2ae1e9062859",