mesa: Don't set shaderapi dispatch pointers for many things in ES2 or core

mesa: Don't set shaderapi dispatch pointers for many things in ES2 or core

v2: Allow GL_ARB_shader_objects functions in core profile because we
still expose the extension string there.  Don't allow
glBindFragDataLocation in GLES3 because it's not part of that API.
Based (mostly) on review comments from Eric Anholt.

NOTE: This is a candidate for the 9.0 branch

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Eric Anholt <eric@anholt.net>