rebase: check no-op before checking phase (issue3891) This could lead to user confusion, because phases aren't really involved at all when attempting to perform a no-op rebase.

template: call runtemplate on the src argument to sub This allows using a template keyword on calls to the sub function and brings the function inline with most other semantics of the other template functions.

run-tests: introduce --random for running tests in random error This is convenient when investigating failures one by one to avoid running the same fixed tests first every time.