test: add a new program for testing ino_release_cb

test: add a new program for testing ino_release_cb

Create a bunch of files and get their inode numbers. Remount, look them
all up by inode number and hold references. Stop looking up inodes as
soon as we get a callback from libcephfs. If we got the callback, return
success. Fail otherwise.

Since this has the same cluster setup as the other client_trim_caps
testcase, we can piggyback onto that task.

Signed-off-by: Jeff Layton <jlayton@redhat.com>