Quoth myself on May 17 at  4:45 pm:
> This adds two known-broken tests and one working test related to the
> term positions assigned to terms from different headers or MIME parts.
> The first test fails because we don't create a termpos gap between
> different headers.  The second test fails because we don't adjust
> termpos at all when indexing multiple parts.

After sending this I realized that we already have some very closely
related tests in T110-search-position-overlap-bug.  These tests should
probably all be together, though obviously the tests I just sent
wouldn't belong in something called "search-position-overlap-bug".