Commit 9aa3c782 added code to allow CREATE TABLE/CREATE TYPE to not fail
when the desired type name conflicts with an autogenerated array type, by
dint of renaming the array type out of the way.  But I (tgl) overlooked
that the same case arises in ALTER TABLE/TYPE RENAME.  Fix that too.
Back-patch to all supported branches.

Report and patch by Vik Fearing, modified a bit by me

Discussion: https://postgr.es/m/0f4ade49-4f0b-a9a3-c120-7589f01d1eb8@2ndquadrant.com