Roll spirv-headers and spirv-tools

Roll src/third_party/spirv-headers/src/ 2c512180c..dcf23bdab (1 commit)

$ git log 2c512180c..dcf23bdab --date=short --no-merges --format='%ad %ae %s'
2018-09-06 cepheus Headers for revision 4 of SPIR-V 1.3, including SPV_KHR_vulkan_memory_model.

Roll src/third_party/SPIRV-Tools/src/ 21bcb9d8b..7600fc0e1 (2 commits)

$ git log 21bcb9d8b..7600fc0e1 --date=short --no-merges --format='%ad %ae %s'
2018-09-05 dneto Update Dim capabilities
2018-06-01 dneto Support SPV_KHR_vulkan_memory_model rev2

Created with:
  roll-dep src/third_party/SPIRV-Tools/src

TBR=dneto@chromium.org

Change-Id: Idd3e61f9aaa01a5787465fefc20f2c232d828a08
Reviewed-on: https://chromium-review.googlesource.com/1211428Reviewed-by: dsinclair <dsinclair@chromium.org>
Commit-Queue: dsinclair <dsinclair@chromium.org>
Cr-Commit-Position: refs/heads/master@{#589312}

DEPS

@@ -213,11 +213,11 @@ 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': '21bcb9d8b9dba1c7b7e1d0a8f5b6ad7ea26cc5b6',
+  'spv_tools_revision': '7600fc0e19c3a99bd3ef2c24515cc508ca1d3cfb',
   # 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_headers_revision': '2c512180ca03b5d4f56283efc85745775b45fdc4',
+  'spv_headers_revision': 'dcf23bdabacc3c54b83b1f9367e7a8adb27f8d87',
 }
 
 # Only these hosts are allowed for dependencies in this DEPS file.