Test "options=-crole=" and "ALTER DATABASE SET role".

Test "options=-crole=" and "ALTER DATABASE SET role".

Commit 7b88529f4363994450bd4cd3c172006a8a77e222 fixed a regression
spanning these features, but it didn't test them.  It did test code
paths sufficient for their present implementations, so no back-patch.

Reported by Matthew Woodcraft.

Discussion: https://postgr.es/m/87iksnsbhx.fsf@golux.woodcraft.me.uk