[3/4] aarch64: Convert UABAL and SABAL patterns to standard RTL codes

[3/4] aarch64: Convert UABAL and SABAL patterns to standard RTL codes

With the SABDL and UABDL patterns converted, the accumulating forms of them UABAL and SABAL are not much more complicated.
There's an accumulator argument that we, err, accumulate into with a PLUS once all the widening is done.
Some necessary renaming of patterns relating to the removal of UNSPEC_SABAL and UNSPEC_UABAL is included.

Bootstrapped and tested on aarch64-none-linux-gnu.

gcc/ChangeLog:

	* config/aarch64/aarch64-simd.md (aarch64_<sur>abal<mode>): Rename to...
	(aarch64_<su>abal<mode>): ... This.  Use RTL codes instead of unspec.
	(<sur>sadv16qi): Rename to...
	(<su>sadv16qi): ... This.  Adjust for the above.
	* config/aarch64/aarch64-sve.md (<sur>sad<vsi2qi>): Rename to...
	(<su>sad<vsi2qi>): ... This.  Adjust for the above.
	* config/aarch64/aarch64.md (UNSPEC_SABAL, UNSPEC_UABAL): Delete.
	* config/aarch64/iterators.md (ABAL): Delete.
	(sur): Remove handling of UNSPEC_SABAL and UNSPEC_UABAL.