Add support for OpenGL ES 3.2 features and shader constants
- Shaders are generated with the version string
appropriate for the running context version.
- Add tests for tessellation shader constants:
- gl_MaxTessControlImageUniforms
- gl_MaxTessEvaluationImageUniforms
- gl_MaxTessControlAtomicCounters
- gl_MaxTessEvaluationAtomicCounters
- gl_MaxTessControlAtomicCounterBuffers
- gl_MaxTessEvaluationAtomicCounterBuffers
- Validate corresponding extension support
for the running context.
Change-Id: Ie11f610a2f7de35b31b9f0b4df31d8af5ca986fe