Remove unused regression test files.

Heikki Linnakangas <heikki.linnakangas@iki.fi>

Commit: d0cab7903bf695bf305bd4c01f99e0e28d233d91
Author: Heikki Linnakangas <heikki.linnakangas@iki.fi>
Date: 2013-05-18T19:35:37Z
Releases: 9.3.0
Remove unused regression test files.

euc_* and mule_internal test cases were identical to the ones in
src/test/mb. sql_ascii didn't exist elsewhere, but has been broken since
2001, and doesn't seem very interesting anyway. drop.sql hasn't been used
since 2000, when regress.sh was removed.

Files