mesa: Returns a GL_INVALID_VALUE error on several APIs when buffer size is negative

mesa: Returns a GL_INVALID_VALUE error on several APIs when buffer size is negative

Section 2.3.1 (Errors) of the OpenGL 4.5 spec says:

    "If a negative number is provided where an argument of type sizei or
    sizeiptr is specified, an INVALID_VALUE error is generated.

This patch adds checks for negative buffer size values passed to different APIs.
It also moves up the check on other APIs that already had it, making it the first
error check performed in the function, for consistency.

While there may be other APIs throughtout the code lacking this check (or at least
not at the beginning of the function), this patch focuses on the cases that break
the dEQP tests listed below. It could be a good excersize for the future to check
all other cases, and improve consistency in the order of the checks throughout the
whole Mesa code base.

This fixes 5 dEQP test:
* dEQP-GLES3.functional.negative_api.state.get_attached_shaders
* dEQP-GLES3.functional.negative_api.state.get_shader_source
* dEQP-GLES3.functional.negative_api.state.get_active_uniform
* dEQP-GLES3.functional.negative_api.state.get_active_attrib
* dEQP-GLES3.functional.negative_api.shader.program_binary

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>