glapi: Move PrimitiveBoundingBox and BlendBarrier definitions into ES3.2 category.

glapi: Move PrimitiveBoundingBox and BlendBarrier definitions into ES3.2 category.

These two GLES 3.2 entry points were being defined in the category of
the ARB_ES3_2_compatibility and KHR_blend_equation_advanced extensions
respectively instead of in the ES3.2 category.  Defining them in the
ES3.2 category makes sure that the gl_procs.py generator emits
declarations in the glprocs.h header file for the unsuffixed GLES-only
entry points that PrimitiveBoundingBoxARB and BlendBarrierKHR
respectively alias.  This should avoid a compilation failure during
scons builds in combination with "mapi: export all GLES 3.2 functions
in libGLESv2.so".

Cc: mesa-stable@lists.freedesktop.org
Reviewed-by: Dylan Baker <dylan@pnwbakers.com>