When copying types from one CTF container to another, ensure that we

When copying types from one CTF container to another, ensure that we
always copy intrinsic data types before copying bitfields which are
based on those types. This ensures the type ordering in the destination
CTF container matches the assumption made elsewhere in the CTF code
that instrinsic data types will always appear before bitfields based on
those types.

This resolves the following error message some users have seen after
r366908:
    "/usr/lib/dtrace/ipfw.d", line 121: failed to copy type of 'ip6p':
    Conflicting type is already defined

Reviewed by:	markj
Sponsored by:	Netflix
Differential Revision:	https://reviews.freebsd.org/D27213