qa: test same-name instance rename

Use the simplified command and rapi version to perform an instance
rename to the same name. This is performed anytime the rename test is
enabled, while the "other-name" rename is performed when also an
alternative name is provided.

Signed-off-by: Guido Trotter <ultrotter@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>