vfstest: split out remaining idmapped mount tests

Split out all the remaining idmapped mount tests into the idmapped
mounts source file.

Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Zorro Lang <zlang@kernel.org>
5 files changed