This patch intends to implement all entry points related to Vertex
Attrib Binding.

(1) Add entry points and validation code on following APIs:
   - VertexAttribFormat
   - VertexAttribIFormat
   - VertexAttribBinding
   - BindVertexBuffer
   - VertexBindingDivisor
(2) Add queries on following parameters:
   - VERTEX_ATTRIB_BINDING
   - VERTEX_ATTRIB_RELATIVE_OFFSET
   - VERTEX_BINDING_DIVISOR
   - VERTEX_BINDING_OFFSET
   - VERTEX_BINDING_STRIDE
   - VERTEX_BINDING_BUFFER

BUG=angleproject:1593

TEST=angle_end2end_tests
TEST=angle_unittests
TEST=dEQP-GLES31.functional.state_query.integer.max_vertex_attrib_relative_offset_*
TEST=dEQP-GLES31.functional.state_query.integer.max_vertex_attrib_bindings_*
TEST=dEQP-GLES31.functional.state_query.integer.max_vertex_attrib_stride_*
TEST=dEQP-GLES31.functional.state_query.vertex_attribute_binding.*
TEST=dEQP-GLES31.functional.debug.negative_coverage.log.vertex_array.vertex_attrib_pointer
TEST=dEQP-GLES31.functional.debug.negative_coverage.get_error.vertex_array.vertex_attrib_format
TEST=dEQP-GLES31.functional.debug.negative_coverage.get_error.vertex_array.vertex_attrib_i_format

Change-Id: I4b477a82df6aad89b89b088580a06d66963e6666
Reviewed-on: https://chromium-review.googlesource.com/446124
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>