Remove std::move that is breaking chromium roll

This is causing the following error:

moving a temporary object prevents copy elision
[-Werror,-Wpessimizing-move]

Add a couple missing headers to the GN build.

Fix warning: size_t->int implicit cast

Detected with ANGLE's export_targets script.

Add option ENABLE_CTEST to skip testing

More aggressively prune unreachable code as follows.
When no control flow edges reach a merge block or continue target:
- delete their contents so that:
  - a merge block becomes OpLabel, then OpUnreachable
  - a continue target becomes OpLabel, then an OpBranch back to the
    loop header
- any basic block which is dominated by such a merge block or continue
  target is removed as well.
- decorations targeting the removed instructions are removed.

Enables the SPIR-V builder post-processing step the GLSLANG_WEB case.

Update spirv-tools known good.

Make  buildbot licenses consistent with the rest of the code

Web: Extend with compute stage, SSBOs, and atomics on SSBO memory.

The Fuchsia platform build and the Chromium one use a completely
different set of configs to specify default warnings. The previous
version of BUILD.gn worked with Chromium, but failed to build
with Fuchsia.

This CL fixes the issue by identifying said configs and reusing
them consistently.

Change-Id: I7de526a57d2f14eb93c03e06401d2c3059d35e9a

Looks like will add about 1K compressed size to executable footprint.

Add Bazel build files and bots for them

Only apply volatile semantics to atomics when using Vulkan Memory Model

In order to avoid potential build failures that could arise from
SPIRV-Tools/Headers, and to avoid reading known_good.json, this build
configuration does not build the SPIRV-Tools dependency and hence cannot
perform HLSL compilation to SPIR-V.

Make runtests configurable.

Fix config issues and revert previous fixes for semi-colon issues