Right now, TransformationRecordSynonymousConstants requires the type
ids of two candidate constants to be exactly the same.
This PR adds an exception for integer constants, which can be
considered equivalent even if their signedness is different.
This applies to both integers and vector constants.

The IsApplicable method of ReplaceIdWithSynonym is also updated so
that, in the case of two integer constants which don't have the same
type, they can only be swapped in particular instructions (those
that don't take the signedness into consideration).

Fixes KhronosGroup#3536.

* Rolling 2 dependencies and updating expectations

Roll third_party/spirv-cross/ 6575e451f..0376576d2 (5 commits)

KhronosGroup/SPIRV-Cross@6575e45...0376576

$ git log 6575e451f..0376576d2 --date=short --no-merges --format='%ad %ae %s'
2020-07-22 tommek Enabling setting a fixed sampleMask in Metal fragment shaders.
2020-02-20 cdavis MSL: Add support for processing more than one patch per workgroup.
2020-07-22 dsinclair Roll GLSLang, SPIRV-Headers and SPIRV-Tools.
2020-07-22 cdavis MSL: Factor creating a uint type into its own method.
2020-07-22 cdavis MSL: Factor a really gnarly condition into its own method.

Created with:
  roll-dep third_party/spirv-cross

Roll third_party/spirv-tools/ 969f028..b63f0e5 (13 commits)

KhronosGroup/SPIRV-Tools@969f028...b63f0e5

$ git log 969f028..b63f0e5 --date=short --no-merges --format='%ad %ae %s'
2020-07-27 rdb Fix SyntaxWarning in Python 3.8 (KhronosGroup#3388)
2020-07-27 bclayton CMake: Enable building with BUILD_SHARED_LIBS=1 (KhronosGroup#3490)
2020-07-27 dneto Avoid operand type range checks (KhronosGroup#3379)
2020-07-27 jaebaek Preserve debug info in scalar replacement pass (KhronosGroup#3461)
2020-07-27 pierremoreau Update OpenCL capabilities validation (KhronosGroup#3149)
2020-07-27 stevenperron build(deps): bump lodash from 4.17.15 to 4.17.19 in /tools/sva (KhronosGroup#3596)
2020-07-27 antonikarp spirv-fuzz: adds TransformationReplaceLoadStoreWithCopyMemory (KhronosGroup#3586)
2020-07-27 jaebaek Preserve OpenCL.DebugInfo.100 through private-to-local pass (KhronosGroup#3571)
2020-07-27 stefanomil spirv-fuzz: Relax type checking for int contants (KhronosGroup#3573)
2020-07-27 stefanomil spirv-fuzz: Generalise transformation access chain (KhronosGroup#3546)
2020-07-27 stefanomil spirv-fuzz: Split blocks starting with OpPhi before trying to outline (KhronosGroup#3581)
2020-07-27 afdx spirv-fuzz: Set message consumer in replayer when shrinking (KhronosGroup#3591)
2020-07-24 vasniktel spirv-fuzz: Don't use default parameters (KhronosGroup#3583)

Created with:
  roll-dep third_party/spirv-tools

* Add in missing expectations update