testsuite, rs6000: Remove useless powerpc_{altivec,vsx}_ok

Checking the existing powerpc_{altivec,vsx}_ok test cases,
I found there are some test cases which don't require the
checks powerpc_{altivec,vsx} even, some of them already
have other effective target check which can cover check
powerpc_{altivec,vsx}, or some of them don't actually
require VSX/AltiVec feature at all.  So this patch is to
remove such useless checks.

	PR testsuite/114842

gcc/testsuite/ChangeLog:

	* gcc.target/powerpc/amo2.c: Remove powerpc_vsx_ok effective target
	check as p9vector_hw already covers it.
	* gcc.target/powerpc/p9-sign_extend-runnable.c: Likewise.
	* gcc.target/powerpc/clone2.c: Remove powerpc_vsx_ok effective target
	check as ppc_cpu_supports_hw already covers it.
	* gcc.target/powerpc/pr47251.c: Remove powerpc_vsx_ok effective target
	check as it doesn't need VSX.
	* gcc.target/powerpc/pr60137.c: Likewise.
	* gcc.target/powerpc/pr80098-1.c: Likewise.
	* gcc.target/powerpc/pr80098-2.c: Likewise.
	* gcc.target/powerpc/pr80098-3.c: Likewise.
	* gcc.target/powerpc/sd-pwr6.c: Likewise.
	* gcc.target/powerpc/pr57744.c: Remove powerpc_vsx_ok effective target
	check and option -mvsx as it doesn't need VSX.
	* gcc.target/powerpc/pr69548.c: Remove powerpc_vsx_ok effective target
	check as it doesn't need VSX, remove lp64 and use int128 instead.
	* gcc.target/powerpc/vec-cmpne-long.c: Remove powerpc_vsx_ok effective
	target check as p8vector_hw already covers it.
	* gcc.target/powerpc/darwin-save-world-1.c: Remove powerpc_altivec_ok
	effective target check as vmx_hw already covers it.