VAX: Actually produce QImode and HImode `ctz' operations

VAX: Actually produce QImode and HImode `ctz' operations

The middle end does not refer to `ctzqi2'/`ctzhi2' or `ffsqi2'/`ffshi2'
patterns by name where `__builtin_ctz' or `__builtin_ffs' respectively
is invoked for an argument of the QImode or HImode type, and instead it
extends the data type before passing it to `ctzsi2' or `ffssi2'.

Avoid the redundant operation and use a peephole2 to convert it to the
right RTL expression that will collapse the two operations into a single
machine instruction instead unless we need the extended intermediate
result for another purpose.

	gcc/
	* config/vax/builtins.md: Add a peephole2 for QImode and HImode
	`ctz' operations.
	(any_extend): New code iterator.

	gcc/testsuite/
	* gcc.target/vax/ctzhi.c: New test.
	* gcc.target/vax/ctzqi.c: New test.
	* gcc.target/vax/ffshi.c: New test.
	* gcc.target/vax/ffsqi.c: New test.