Use GLSLANG_ANGLE to strip features to what ANGLE requires

Revert changes that migrate to `thread_local`.

This change strips a few features similar to GLSLANG_WEB but doesn't
remove every detail like the latter.  It also hardcodes profile/version
to core/450.

In particular, TBuiltIns::initialize is specialized to remove most of
what is not supported or won't be supported by ANGLE.  The result of
this function is parsed with TParseContext::parseShaderStrings which is
a performance bottleneck.

This change shaves about 300KB off of ANGLE's binary size and reduces
the cost of SetupBuiltinSymbolTable to nearly a sixth.
Signed-off-by: Shahbaz Youssefi <ShabbyX@gmail.com>

iOS 8 does not support `thread_local`, which is still in use.
Another approach will have to be found.

This change is a revert of the following changes:

a3845240 - "Simplify PoolAlloc with use of thread_local."
abf92c80 - "Deprecate InitializeDll functions"
33585c87 - "Limit visibility of symbols for internal libraries"

Issue: #2346

Avoid spurious warning about uninit var

Update spirv-tools known-good to most recent stable

Add changes for SPV_EXT_shader_atomic_float_add

Limit visibility of symbols for internal libraries

Also remove `SPIRV/doc.cpp` from the `SPVRemapper` target as this
is part of `SPIRV`, causing ODR violations. Instead have
`SPVRemapper` link against `SPIRV`.

Fixes ODR violations.

Simplify PoolAlloc by using `thread_local`

also search global sequences for live variables

These were only used for TThreadPool, which now uses `thread_local`.

glslang is using C++ 11, which has first class support for variables of the `thread_local` storage class.

By dropping the use of the `OS_[GS]etTLSValue`, we can simplify the logic, and have it support a thread-local default allocator if none is provided.

Issue: #2346

Finalize glslang 10.15.3847, start glslang 11, drop support for VS2013

when traversing the AST to find live UBOs etc, also traverse
references to global module-level variables, incase they are
being filled in from UBOs etc.

This was scheduled for today - 20th July 2020.

Updates Appveyor configs to use VS2015 instead.

Update license-checker.cfg with simplified rules

`license-checker` has been updated to support `**` wildcards simplifying the ruless, and multiple license configs.

Add a new config for the bison generated files to ensure their licenses don't change.

Add new rules for update of license-checker

`license-checker` will be updated to support `**` based wildcards. As part of this, `license-checker` will now traverse into subdirectories that would previously be excluded when the parent directory is excluded.

This change adds new rules that work with both the old version and new, to ease migration.

GLSL/SPV: Propagaet precision qualifier from function to return value.

When a return value's type has no precision qualification (e.g., the return
expression is formed from a constructor), and the formal function return type
has a precision qualification, back propagate that from the return type to the
type of the return value's expression.

runtests: Check error codes, set LD_LIBRARY_PATH

`glslangValidator` will only return [the codes 0..6](https://github.com/KhronosGroup/glslang/blob/b481744aea1ecf52ee4591afaa0f5e270b9d1636/StandAlone/StandAlone.cpp#L117-L125). Fail the test if anything else is returned (like due to the exe crashing).

Also set `LD_LIBRARY_PATH` to contain the `lib` directory before calling glslang.

Kokoro: Print test output to stdout

Give build_info.py the executable bit

Fix recently found non-determinism with gl_WorldToObject3x4EXT.

CMake: Move project() to top of CMakeLists.txt