Add support for GL_EXT_YUV_target

Hopefully, this fixes the sudden new breakage with the bots.

Reflection consistency changes & bugfixes

* Previously the offset was only updated with EOpIndexDirectStruct, but we also
  need to update it for the other index types into arrays, and when expanding an
  aggregate reached after dereferencing.

Update spirv-tools known-good.

build: Do not cache debug library suffix

For nested project builds, writing CMAKE_DEBUG_POSTFIX into the cache
ends up affecting other projects. Caching this value doesn't seem to be
required in practice, so this change removes the cache tag.

Suppress a MSVC cast warning in GN.

Also came up when using the BUILD.gn file with ANGLE.

ANGLE bug: 3088

Add extension checks for NV block member builtins

Suppress inconsistent override warning in GN.

This came up when trying to roll the new glslang into Chromium.

ANGLE bug: 3088

Infrastructure: Generalize and broaden per-variable extension checking.

Fix a few GN build issues.

More precisely check for the qualifiers that enable the vulkan memory model for buffer references.

Not all memory qualifiers necessarily need the vulkan memory model, e.g. volatile/restrict that correspond to core SPIR-V features do not.

 * adds a source set for default resource limits to mirror CMake
 * adds a target executable for the standalone validator
 * fixes a missing warning

Allows ANGLE to use the integrated BUILD.gn instead of a custom one.

ANGLE bug: 3088

Fix xfb_stride incorrectness(#1654)

HLSL: Avoid leaking a shadow sampler struct

Avoid leaking name for counter buffer

HLSL: Fix #1655; use "" for nullptr file names

Add int64 support in XFB. Change containsDouble to contains64BitType. Make
it more general.

Work around a CMake cross-compilation issue

Update SPIRV-Tools known good: relax Uconvert check

Permit UConvert as an OpSpecConstantOp operation when
SPV_AMD_gpu_shader_int_16 is used.

Parenthesize to avoid GCC warning