[APX CCMP] Use ctestcc when comparing to const 0

[APX CCMP] Use ctestcc when comparing to const 0

For CTEST, we don't have conditional AND so there's no optimization
opportunity to write a new ctest pattern. Emit ctest when ccmp did
comparison to const 0 to save bytes.

gcc/ChangeLog:

	* config/i386/i386.md (@ccmp<mode>): Add new alternative
	<r>,C and adjust output templates. Also adjust UNSPEC mode
	to CCmode.

gcc/testsuite/ChangeLog:

	* gcc.target/i386/apx-ccmp-1.c: Adjust output to scan ctest.
	* gcc.target/i386/apx-ccmp-2.c: Adjust some condition to
	compare with 0.