aarch64: Use VNx16BI for svrev_b* [PR121294]

aarch64: Use VNx16BI for svrev_b* [PR121294]

The previous patch for PR121294 handled svtrn1/2, svuzp1/2, and svzip1/2.
This one extends it to handle svrev intrinsics, where the same kind of
wrong code can be generated.

gcc/
	PR target/121294
	* config/aarch64/aarch64.md (UNSPEC_REV_PRED): New unspec.
	* config/aarch64/aarch64-sve.md (@aarch64_sve_rev<mode>_acle)
	(*aarch64_sve_rev<mode>_acle): New patterns.
	* config/aarch64/aarch64-sve-builtins-base.cc
	(svrev_impl::expand): Use the new patterns for boolean svrev.

gcc/testsuite/
	PR target/121294
	* gcc.target/aarch64/sve/acle/general/rev_2.c: New test.