arm/97903: Missed optimization in lowering test operation.

gcc/ChangeLog:

2021-05-05  Prathamesh Kulkarni  <prathamesh.kulkarni@linaro.org>

	* config/arm/neon.md (neon_vtst_combine<mode>): New pattern.
	* config/arm/predicates.md (minus_one_operand): New predicate.