VAX: Use an int iterator to produce individual interlocked branches

VAX: Use an int iterator to produce individual interlocked branches

With mode-specific interlocked branch insns already folded into iterated
templates now fold the two templates into one too, observing that the
only difference between them is the value of the bit branched on, which
is of course reflected both in the RTL expression and the instruction
produced.  Use an int iterator to iterate over the bit value, making use
of the newly-added wide integer support, and substituting patterns as
necessary to produce equivalent individual insns.  No functional change.

	gcc/
	* config/vax/builtins.md (bit): New int iterator.
	(ccss): New int attribute.
	(jbbssi<mode>, jbbcci<mode>): Fold insns into...
	(jbb<ccss>i<mode>): ... this.