Roll SPIRV-Tools from 6a4da9da4215 to 7afbc0c8be3f (3 revisions)

https://chromium.googlesource.com/external/github.com/KhronosGroup/SPIRV-Tools.git/+log/6a4da9da4215..7afbc0c8be3f

2020-07-07 andreperezmaselco.developer@gmail.com spirv-fuzz: Add variables with workgroup storage class (#3485)
2020-07-07 andreperezmaselco.developer@gmail.com spirv-fuzz: Implement the OpVectorTimesMatrix linear algebra case (#3489)
2020-07-07 vasniktel@gmail.com spirv-fuzz: fuzzerutil::MaybeGetConstant* #3487

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/spirv-tools-chromium-autoroll
Please CC radial-bots+chrome-roll@google.com,syoussefi@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

Cq-Include-Trybots: luci.chromium.try:android_angle_vk32_deqp_rel_ng;luci.chromium.try:android_angle_vk32_rel_ng;luci.chromium.try:android_angle_vk64_deqp_rel_ng;luci.chromium.try:android_angle_vk64_rel_ng;luci.chromium.try:linux_angle_deqp_rel_ng;luci.chromium.try:linux-angle-rel;luci.chromium.try:win-angle-rel-32;luci.chromium.try:win-angle-rel-64;luci.chromium.try:win-angle-deqp-rel-32;luci.chromium.try:win-angle-deqp-rel-64
Tbr: radial-bots+chrome-roll@google.com,syoussefi@google.com
Change-Id: I18d8b33b213d65919e1726e6531750cac073af87
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2286780Reviewed-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@{#786213}

DEPS

@@ -306,7 +306,7 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling feed
   # and whatever else without interference from each other.
-  'spv_tools_revision': '6a4da9da421560f3f2b073e4e8e4691787c3c732',
+  'spv_tools_revision': '7afbc0c8be3f4dd48a7e521deb18f5c29a6c9892',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling feed
   # and whatever else without interference from each other.