compiler/types: Add helpers to get explicit types for standard layouts

compiler/types: Add helpers to get explicit types for standard layouts

We also need to modify the current size/align helpers to not blow up
when they encounter an explicitly laid out type.  Previously we
considered using the size/align helpers mutually exclusive with standard
layouts but now we just assert that they match.

Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>