mesa: Considers GL_DEPTH_STENCIL_ATTACHMENT a valid argument for FBO invalidation under GLES3

In GLES3, GL_DEPTH_STENCIL_ATTACHMENT is a valid attachment point for the family of functions
that invalidate a framebuffer object (e.g, glInvalidateFramebuffer, glInvalidateSubFramebuffer).
Currently, a GL_INVALID_ENUM error is emitted for this attachment point.

Fixes 21 dEQP test failures under 'dEQP-GLES3.functional.fbo.invalidate.*'.
mesa: Enables GL_RGB and GL_RGBA unsized internal formats for OpenGL ES 3.0

GL_RGB and GL_RGBA are valid internal formats on a GLES3 profile. See
"Table 1. Unsized Internal Formats" at
https://www.khronos.org/opengles/sdk/docs/man3/html/glTexImage2D.xhtml.

Fixes 2 dEQP tests:
- dEQP-GLES3.functional.state_query.internal_format.rgb_samples
- dEQP-GLES3.functional.state_query.internal_format.rgba_samples
mesa: Returns zero samples when querying GL_NUM_SAMPLE_COUNTS when internal format is integer

In GLES3, multisampling is not supported for signed and unsigned integer
internal formats. See https://www.khronos.org/opengles/sdk/docs/man3/docbook4/xhtml/glGetInternalformativ.xml.

Fixes 19 dEQP tests under 'dEQP-GLES3.functional.state_query.internal_format.*'.
mesa: Recompute LegalTypesMask if the GL API has changed

The current code computes ctx->Array.LegalTypesMask just once,
however, computing this needs to consider ctx->API so we need
to make sure that the API for that context has not changed if
we intend to reuse the result.

The context API can change, at least, if we go through
_mesa_meta_begin, since that will always force
API_OPENGL_COMPAT until we call _mesa_meta_end. If any
operation in between these two calls triggers a call to
update_array_format, then we might be caching a value for
LegalTypesMask that will not be right once we have called
_mesa_meta_end and restored the context API.

Fixes the following 179 dEQP tests in i965:
dEQP-GLES3.functional.vertex_arrays.single_attribute.strides.fixed.*
dEQP-GLES3.functional.vertex_arrays.single_attribute.normalize.fixed.*
dEQP-GLES3.functional.vertex_arrays.single_attribute.output_types.fixed.*
dEQP-GLES3.functional.vertex_arrays.single_attribute.usages.static_draw.*fixed*
dEQP-GLES3.functional.vertex_arrays.single_attribute.usages.stream_draw.*fixed*
dEQP-GLES3.functional.vertex_arrays.single_attribute.usages.dynamic_draw.*fixed*
dEQP-GLES3.functional.vertex_arrays.single_attribute.usages.static_copy.*fixed*
dEQP-GLES3.functional.vertex_arrays.single_attribute.usages.stream_copy.*fixed*
dEQP-GLES3.functional.vertex_arrays.single_attribute.usages.dynamic_copy.*fixed*
dEQP-GLES3.functional.vertex_arrays.single_attribute.usages.static_read.*fixed*
dEQP-GLES3.functional.vertex_arrays.single_attribute.usages.stream_read.*fixed*
dEQP-GLES3.functional.vertex_arrays.single_attribute.usages.dynamic_read.*fixed*
dEQP-GLES3.functional.vertex_arrays.multiple_attributes.input_types.3_*fixed2*
dEQP-GLES3.functional.draw.random.{2,18,28,68,83,106,109,156,181,191}