Fixes to regression tests

The regression test now returns a non-zero exit code so `make test` fails if a test fails. There were some regressions that weren't getting caught because of this.

The change in d87de4d resulted in removing a test that didn't make sense because of a recent change. I stared at it for a while and finally decided that the original test was written didn't make sense, as it's trying to perform time zone transformation tricks that shouldn't be possible given comments in other parts of the code. Another pair of eyes to confirm would be good though.