RISC-V: Adjust the gather-scatter testcases due to middle-end change

RISC-V: Adjust the gather-scatter testcases due to middle-end change

After we have MASK_LEN_STRIDED_LOAD{STORE} in the middle-end, the
strided case need to be adjust for IR check.

The below test suites are passed for this patch:
* The riscv fully regression test.

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/rvv/autovec/gather-scatter/strided_load-1.c:
	Adjust IR for MASK_LEN_LOAD check.
	* gcc.target/riscv/rvv/autovec/gather-scatter/strided_load-2.c:
	Ditto.
	* gcc.target/riscv/rvv/autovec/gather-scatter/strided_store-1.c:
	Ditto but for store.
	* gcc.target/riscv/rvv/autovec/gather-scatter/strided_store-2.c:
	Ditto.

Signed-off-by: Pan Li <pan2.li@intel.com>
Co-Authored-By: Juzhe-Zhong <juzhe.zhong@rivai.ai>