i386: Add new pattern for zero-extend cmov

After a phiopt change, I got a failure of cmov9.c.
The RTL IR has zero_extend on the outside of
the if_then_else rather than on the side. Both
ways are considered canonical as mentioned in
PR 66588.

This fixes the failure I got and also adds a testcase
which fails before even my phiopt patch but will pass
with this patch.

OK? Bootstrapped and tested on x86_64-linux-gnu with
no regressions.

gcc/ChangeLog:

	* config/i386/i386.md (*movsicc_noc_zext_1): New pattern.

gcc/testsuite/ChangeLog:

	* gcc.target/i386/cmov10.c: New test.
	* gcc.target/i386/cmov11.c: New test.