testsuite, rs6000: Remove powerpcspe test cases and checks

Since r9-4728 the powerpcspe support had been removed, this
follow-up patch is to remove the remaining pieces in testsuite.

gcc/testsuite/ChangeLog:

	* lib/target-supports.exp
	(check_effective_target_vect_cmdline_needed): Remove
	check_effective_target_powerpc_spe.
	(check_effective_target_powerpc_spe_nocache): Remove.
	(check_effective_target_powerpc_spe): Remove.
	(check_ppc_cpu_supports_hw_available): Remove powerpc*-*-eabispe check.
	(check_p8vector_hw_available): Likewise.
	(check_p9vector_hw_available): Likewise.
	(check_p9modulo_hw_available): Likewise.
	(check_ppc_float128_sw_available): Likewise.
	(check_ppc_float128_hw_available): Likewise.
	(check_vsx_hw_available): Likewise.
	(check_vmx_hw_available): Likewise.
	(check_ppc_recip_hw_available): Likewise.
	(check_dfp_hw_available): Likewise.
	(check_htm_hw_available): Likewise.
	* g++.dg/ext/spe1.C: Remove.
	* g++.dg/other/opaque-1.C: Remove.
	* g++.dg/other/opaque-2.C: Remove.
	* g++.dg/other/opaque-3.C: Remove.
	* g++.target/powerpc/simd-5.C: Remove.