VAX: Unify push operation selection

VAX: Unify push operation selection

Avoid the possibility of code discrepancies like one fixed with the
previous change and improve the structure of code by selecting between
push and non-push operations in a single place in `vax_output_int_move'.

The PUSHAB/MOVAB address moves are never actually produced from this
code as the SImode invocation of this function is guarded with the
`nonsymbolic_operand' predicate, but let's not mess up with this code
too much on this occasion and keep the piece in place.

	* config/vax/vax.c (vax_output_int_move): Unify push operation
	selection.