rs6000: Implement optab_isinf for SFDF and IEEE128

rs6000: Implement optab_isinf for SFDF and IEEE128

gcc/
	PR target/97786
	* config/rs6000/rs6000.md (constant VSX_TEST_DATA_CLASS_NAN,
	VSX_TEST_DATA_CLASS_POS_INF, VSX_TEST_DATA_CLASS_NEG_INF,
	VSX_TEST_DATA_CLASS_POS_ZERO, VSX_TEST_DATA_CLASS_NEG_ZERO,
	VSX_TEST_DATA_CLASS_POS_DENORMAL, VSX_TEST_DATA_CLASS_NEG_DENORMAL):
	Define.
	(mode_attr sdq, vsx_altivec, wa_v, x): Define.
	(mode_iterator IEEE_FP): Define.
	* config/rs6000/vsx.md (isinf<mode>2): New expand.
	(expand xststdcqp_<mode>, xststdc<sd>p): Combine into...
	(expand xststdc_<mode>): ...this.
	(insn *xststdcqp_<mode>, *xststdc<sd>p): Combine into...
	(insn *xststdc_<mode>): ...this.
	* config/rs6000/rs6000-builtin.cc (rs6000_expand_builtin): Rename
	CODE_FOR_xststdcqp_kf as CODE_FOR_xststdc_kf,
	CODE_FOR_xststdcqp_tf as CODE_FOR_xststdc_tf.
	* config/rs6000/rs6000-builtins.def: Rename xststdcdp as xststdc_df,
	xststdcsp as xststdc_sf, xststdcqp_kf as xststdc_kf.

gcc/testsuite/
	PR target/97786
	* gcc.target/powerpc/pr97786-1.c: New test.
	* gcc.target/powerpc/pr97786-2.c: New test.