mesa: Check for valid PBO access in gl(Compressed)Tex(Sub)Image calls

mesa: Check for valid PBO access in gl(Compressed)Tex(Sub)Image calls

This patch adds two types of checks to the gl(Compressed)Tex(Sub)Imgage family
of functions when a pixel buffer object is bound to GL_PIXEL_UNPACK_BUFFER:

- That the buffer is not mapped.
- The total data size is within the boundaries of the buffer size.

It does so by calling auxiliary validations functions from PBO API:
_mesa_validate_pbo_source() for non-compressed texture calls, and
_mesa_validate_pbo_source_compressed() for compressed texture calls.

The first check is defined in Section 6.3.2 'Effects of Mapping Buffers
on Other GL Commands' of the GLES 3.1 spec, page 57:

    "Any GL command which attempts to read from, write to, or change the
     state of a buffer object may generate an INVALID_OPERATION error if all
     or part of the buffer object is mapped. However, only commands which
     explicitly describe this error are required to do so. If an error is not
     generated, using such commands to perform invalid reads, writes, or
     state changes will have undefined results and may result in GL
     interruption or termination."

Similar wording exists in GL 4.5 spec, page 76.

In the case of gl(Compressed)Tex(Sub)Image(2,3)D, the specification doesn't force
implemtations to throw an error. However since Mesa don't currently implement
checks to determine when it is safe to read/write from/to a mapped PBO, we
should always return the error if all or parts of it are mapped.

The 2nd check is defined in Section 8.5 'Texture Image Specification' of the
OpenGL 4.5 spec, page 203:

    "An INVALID_OPERATION error is generated if a pixel unpack buffer object
     is bound and storing texture data would access memory beyond the end of
     the pixel unpack buffer."

Fixes 4 dEQP tests:
* dEQP-GLES3.functional.negative_api.texture.compressedteximage2d_invalid_buffer_target
* dEQP-GLES3.functional.negative_api.texture.compressedtexsubimage2d_invalid_buffer_target
* dEQP-GLES3.functional.negative_api.texture.compressedteximage3d_invalid_buffer_target
* dEQP-GLES3.functional.negative_api.texture.compressedtexsubimage3d_invalid_buffer_target

Reviewed-by: Laura Ekstrand <laura@jlekstrand.net>