glsl: inspect interfaces in contains_foo()

glsl: inspect interfaces in contains_foo()

When checking if a type contains doubles, integers, samples, etc. we
check if the current type is a record or array, but not if it is an
interface.

This commit also inspects if the type is an interface.

It fixes spec/arb_enhanced_layouts/compiler/transform-feedback-layout-qualifiers/xfb_offset/invalid-block-with-double.vert
piglit test.

Reviewed-by: Timothy Arceri <timothy.arceri@collabora.com>