[m-rev.] diff: rename some preds in ml_tailcalls.m

[Peter Wang]

On Wed, 11 Jan 2017 21:04:31 +1100 (AEDT), "Zoltan Somogyi" <zoltan.somogyi at runbox.com> wrote:
> Replace predicate names such "check_rval" with names
> that say what the predicate does.

staf?

Peter