Roll SPIRV-Tools from 2de7d3af0c0e to 726af6f78f80 (6 revisions)

https://chromium.googlesource.com/external/github.com/KhronosGroup/SPIRV-Tools.git/+log/2de7d3af0c0e..726af6f78f80

2020-09-11 afdx@google.com Add missing file to BUILD.gn (#3798)
2020-09-11 antonikarp@google.com spirv-fuzz: Add TransformationDuplicateRegionWithSelection (#3773)
2020-09-11 afdx@google.com spirv-reduce: Support reducing a specific function (#3774)
2020-09-10 afdx@google.com spirv-reduce: Refactoring (#3793)
2020-09-10 afdx@google.com Favour 'integrity' over 'coherence' as a replacement for 'sanity'. (#3619)
2020-09-10 antonikarp@google.com spirv-fuzz: Fix header guards in transformations/fuzzer passes (#3784)

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,jmadill@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,jmadill@google.com
Change-Id: Ic402f57e4e234b9ee88f01864cc5ba2c9fb1e27a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2409372Reviewed-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@{#806570}

DEPS

@@ -302,7 +302,7 @@ 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': '2de7d3af0c0ed8b0fcff7b83b36c5a7424e51e19',
+  'spv_tools_revision': '726af6f78f80988271c8b558ae9cc84fa5a65016',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling feed
   # and whatever else without interference from each other.