RISC-V: Add auto-vect pattern for vector rotate shift

RISC-V: Add auto-vect pattern for vector rotate shift

This patch add the vector rotate shift pattern for auto-vect.
With this patch, the scalar rotate shift can be automatically
vectorized into vector rotate shift.

gcc/ChangeLog:

	* config/riscv/autovec.md (v<bitmanip_optab><mode>3):
	Add new define_expand pattern for vector rotate shift.
gcc/testsuite/ChangeLog:

	* gcc.target/riscv/rvv/autovec/binop/vrolr-1.c: New test.
	* gcc.target/riscv/rvv/autovec/binop/vrolr-run.c: New test.
	* gcc.target/riscv/rvv/autovec/binop/vrolr-template.h: New test.