Support vec_cmpmn/vcondmn for v2hf/v4hf.

gcc/ChangeLog:

	PR target/103861
	* config/i386/i386-expand.cc (ix86_expand_sse_movcc): Handle
	V2HF/V2BF/V4HF/V4BFmode.
	* config/i386/i386.cc (ix86_get_mask_mode): Return QImode when
	data_mode is V4HF/V2HFmode.
	* config/i386/mmx.md (vec_cmpv4hfqi): New expander.
	(vcond_mask_<mode>v4hi): Ditto.
	(vcond_mask_<mode>qi): Ditto.
	(vec_cmpv2hfqi): Ditto.
	(vcond_mask_<mode>v2hi): Ditto.
	(mmx_plendvb_<mode>): Add 2 combine splitters after the
	patterns.
	(mmx_pblendvb_v8qi): Ditto.
	(<code>v2hi3): Add a combine splitter after the pattern.
	(<code><mode>3): Ditto.
	(<code>v8qi3): Ditto.
	(<code><mode>3): Ditto.
	* config/i386/sse.md (vcond<mode><mode>): Merge this with ..
	(vcond<sseintvecmodelower><mode>): .. this into ..
	(vcond<VI2HFBF_AVX512VL:mode><VHF_AVX512VL:mode>): .. this,
	and extend to V8BF/V16BF/V32BFmode.

gcc/testsuite/ChangeLog:

	* g++.target/i386/part-vect-vcondhf.C: New test.
	* gcc.target/i386/part-vect-vec_cmphf.c: New test.