RISC-V: Add more test cases for vwmaccus.vx

For csrr not asm check when enable overlap enabled.

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/rvv/base/pr112431-57.c: New test.
	* gcc.target/riscv/rvv/base/pr112431-58.c: New test.

Signed-off-by: Pan Li <pan2.li@intel.com>