Undo previous change that removed primitive apply optimizations. (It

Undo previous change that removed primitive apply optimizations.  (It
turns out that my analysis was incomplete and further changes would
have been required.)  Fix the problem with the apply hacks by
introducing a new exception code PRIM_APPLY_ERROR, which provides an
alternate path for signaling an error to the interpreter, _without_
backing out of the primitive (since we've already made all the
necessary changes to the stack).