Roll SwiftShader from 2d6b37bbda59 to 3121585acce2 (2 revisions)

https://swiftshader.googlesource.com/SwiftShader.git/+log/2d6b37bbda59..3121585acce2

2020-07-02 sugoi@google.com ASTC Decoder: Trim unused struct members
2020-07-02 capn@google.com Fix /DEBUG:FASTLINK usage

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/swiftshader-angle-autoroll
Please CC ianelliott@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/+doc/master/autoroll/README.md

Bug: None
Tbr: ianelliott@google.com
Change-Id: Ib62019d73da7b873ef816ec2ac469651cbceec55
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2280823
Reviewed-by: angle-autoroll <angle-autoroll@skia-public.iam.gserviceaccount.com>
Commit-Queue: angle-autoroll <angle-autoroll@skia-public.iam.gserviceaccount.com>

DEPS

@@ -203,7 +203,7 @@ deps = {
   },
 
   'third_party/SwiftShader': {
-    'url': '{swiftshader_git}/SwiftShader@2d6b37bbda59247a1f24209ff549ffbf8174e338',
+    'url': '{swiftshader_git}/SwiftShader@3121585acce20f5cc2074088563e3c1a076b8e48',
     'condition': 'not build_with_chromium',
   },