Roll third_party/swiftshader/ bdfcfe9cf..51b2800bb (23 commits)

https://swiftshader.googlesource.com/SwiftShader/+log/bdfcfe9cfd2a..51b2800bb317

$ git log bdfcfe9cf..51b2800bb --date=short --no-merges --format='%ad %ae %s'
2020-01-30 capn Support launching PowerVR samples from Visual Studio using SwiftShader
2020-03-04 amaiorano Subzero: implement Short4::Short4(RValue<Float4)
2020-02-28 amaiorano Subzero: don't assert about lack of atomic load/store on x86
2020-03-04 amaiorano Fix Regres regression post CMake var renaming
2020-03-03 amaiorano Subzero: fix regression in Optimizer
2020-03-03 jrprice Use LINK_FLAGS for -BSymbolic in CMake build
2020-03-03 capn Fix ASTC support for GN build
2020-03-02 swiftshader.regress Regres: Update test lists @ 416d3745
2020-03-01 capn Enable ASTC on supported builds only
2020-02-27 jmadill PipelineCache: Handle nullptr mismatch of specialization info.
2020-02-24 sugoi Implement ASTC support
2020-02-27 jonahr Add missing attribute to eglGetConfigAttrib
2020-02-27 jmadill Add codereview.settings.
2020-02-26 amaiorano Subzero: add support for variadic calls (System V)
2020-02-26 jmadill Fix comparison of specialization constant keys.
2020-02-25 amaiorano Subzero: add support for large stacks on Windows
2020-02-25 capn Build with -Bsymbolic to prevent symbol preemption
2020-02-25 capn Fix ANGLE standalone build
2020-02-25 capn Fix Android build after SPIRV-Tools update
2020-02-19 srisser Log instead of warn of unsupported extensions
2020-02-25 swiftshader.regress Regres: Update test lists @ e162b023
2020-02-24 capn Add SPIRV-Tools headers dependency
2020-02-24 capn Add SPIR-Tools include headers path for src/Pipeline

TBR=enga@chromium.org

Created with:
  roll-dep third_party/swiftshader

Change-Id: I3843e5b647a4ffd36c66896d9f262118f459a107
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/16523
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>

DEPS

@@ -104,7 +104,7 @@ deps = {
   },
 
   'third_party/swiftshader': {
-    'url': '{swiftshader_git}/SwiftShader@bdfcfe9cfd2acb22219dd5a79fd7f83c8f320a11',
+    'url': '{swiftshader_git}/SwiftShader@51b2800bb317d9ab6026e6123c62f013dd5cf5e4',
     'condition': 'dawn_standalone',
   },