st/mesa/r200/i915/i965: use rzalloc() to create gl_program

st/mesa/r200/i915/i965: use rzalloc() to create gl_program

This allows us to use ralloc_parent() to see which data structure owns
shader_info which allows us to fix a regression in nir_sweep().

This will also allow us to move some fields from gl_linked_shader to
gl_program, which will allow us to do some clean-ups like storing
gl_program directly in the CurrentProgram array in gl_pipeline_object
enabling some small validation optimisations at draw time.

Also it is error prone to depend on the gl_linked_shader for
programs in current use because a failed linking attempt will free
infomation about the current program. In i965 we could be trying
to recompile a shader variant but may have lost some required fields.

Reviewed-by: Eric Anholt <eric@anholt.net>