AVX10.2: Support compare instructions

gcc/ChangeLog:

	* config/i386/i386-expand.cc
	(ix86_ssecom_setcc): Mention behavior change on flags.
	(ix86_expand_sse_comi): Handle AVX10.2 behavior.
	(ix86_expand_sse_comi_round): Ditto.
	(ix86_expand_round_builtin): Ditto.
	(ix86_expand_builtin): Change function call.
	* config/i386/i386.md (UNSPEC_COMX): New unspec.
	* config/i386/sse.md
	(avx10_2_v<unord>comx<ssemodesuffix><round_saeonly_name>): New.
	(<sse>_<unord>comi<round_saeonly_name>): Add HFmode.

gcc/testsuite/ChangeLog:

	* gcc.target/i386/avx10_2-compare-1.c: New test.

Co-authored-by: Haochen Jiang <haochen.jiang@intel.com>
Co-authored-by: Hongtao Liu <hongtao.liu@intel.com>