i965: Enable GL_KHR_robustness

GL_KHR_robustness adds the GL_CONTEXT_LOST error and five new entry
points that we already implement.  This patch adds a new dispatch table
that returns GL_CONTEXT_LOST from all entry points and implements the
GL_LOSE_CONTEXT_ON_RESET strategy by setting that table when we learn
that we've lost the context.

With the GL_CONTEXT_LOST reporting in place and dispatch for the new
entry points we can turn on GL_KHR_robustness.

Signed-off-by: Kristian Høgsberg Kristensen <krh@bitplanet.net>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Acked-by: Ilia Mirkin <imirkin@alum.mit.edu>

docs/GL3.txt

@@ -218,7 +218,7 @@ GL 4.5, GLSL 4.50:
   GL_ARB_shader_texture_image_samples                   DONE (i965, nv50, nvc0, r600, radeonsi)
   GL_ARB_texture_barrier                                DONE (i965, nv50, nvc0, r600, radeonsi)
   GL_KHR_context_flush_control                          DONE (all - but needs GLX/EGL extension to be useful)
-  GL_KHR_robustness                                     not started (90% done with the ARB variant)
+  GL_KHR_robustness                                     DONE (i965)
   GL_EXT_shader_integer_mix                             DONE (all drivers that support GLSL)
 
 These are the extensions cherry-picked to make GLES 3.1

docs/relnotes/11.3.0.html

@@ -60,6 +60,7 @@ Note: some of the new features are only available with certain drivers.
 <li>GL_ATI_fragment_shader on all Gallium drivers</li>
 <li>GL_EXT_base_instance on all drivers that support GL_ARB_base_instance</li>
 <li>GL_EXT_clip_cull_distance on all drivers that support GL_ARB_cull_distance</li>
+<li>GL_KHR_robustness on i965</li>
 <li>GL_OES_draw_buffers_indexed and GL_EXT_draw_buffers_indexed on all drivers that support GL_ARB_draw_buffers_blend</li>
 <li>GL_OES_gpu_shader5 and GL_EXT_gpu_shader5 on all drivers that support GL_ARB_gpu_shader5</li>
 <li>GL_OES_sample_shading on i965, nvc0, r600, radeonsi</li>