RFC: run testsuite with -O3

[Andrew Haley]

Tom Tromey writes:
 > Jeff> Does anyone else think this is worthwhile?
 > 
 > I do.
 > 
 > I have a slight preference for keeping -O and just adding -O3.
 > My reasoning is that we're adding -O3 now because we've seen
 > regressions there.  But if we remove -O from testing, at some point I
 > can imagine us wanting to re-enable it due to other regressions.

Well, if you really expect to see regressions at -O3 that don't
trigger at -O1, fair enough.  But know this: the longer the tests
take, the less they will be run by developers.

Andrew.