Including spirv and AST tests

Also increase size of TBuiltInVariable bitfields since we've now exceeded 127
and add a static_assert to make this easier to find next time it happens!

Use spvValidatorOptionsSetBeforeHlslLegalization for pre-legalized HLSL

Uppdate spirv-tools known-good

Remove unused parameter

Add missing NV_EXTENSIONS ifdef

Support GL_ARB_fragment_shader_interlock

Remove glslang.y from gn sources

Fix subgroup support for ray tracing

Closes #1735

GlslangToSpv.cpp
- minor formatting cleanup

BaseTypes.h
- minor formatting cleanup
- add subgroup builtins to GetBuiltInVariableString
  (was resulting in "unknown built-in variable" messages in test output)

Initialize.cpp
- better naming and re-use of strings for subgroup builtin variable declarations
- define subgroup builtin variables in ray-tracing shaders

intermOut.cpp
- add handling of the EOpSubgroupParition* variables
  (was resulting in "ERROR: Bad aggregation op" messages in test output)

Update test results.

with subgroup touch tests (error and non-error cases)
Currently the subgroup built-ins are NOT giving the correct output.
This is fixed in the next commit.

with subgroup touch testing (error and non-error cases)

Add missing symbolTable.relateToOperator("subgroupMemoryBarrierShared") call for
Mesh/Task shaders so they don't assert in ParseHelper.cpp

Touch test all subgroup builtins in vert, tesc, tese, geom, frag, compute shaders
before and after enabling extensions to make sure the correct errors are generated
and then not generated (after enablement).

Allow runtime-sized arrays of acceleration structures

Misc fixes from dgkoch

Don't prefix with "Capability" since the majority of them don't.
Also add missing CapabilityImageFootprintNV

Fixed .dll install on MSVC.

No behavior changes.  Please see [1] for why this is necessary.

[1] https://bugs.chromium.org/p/chromium/issues/detail?id=964411

Build.gn: allow optimization in glslang lib and standalone

Update SPIRV-Tools, SPIRV-Headers

Headers update fixes validation of spv.shaderBallotAMD.

SPV 1.4: Add code generation for SPIR-V 1.4 features

...when doing a variable lookup on an array of constants.

This includes the test for the first feature of OpEntryPoint.