[RISCV Add some vsetvli insertion test cases with vmv.s.x+reduction. NFC (#75544)

These test cases where intended to get a single vsetvli by using the
vmv.s.x intrinsic with the same LMUL as the reduction. This works for
FP, but does not work for integer.

I believe #71501 will break this for FP too. Hopefully the vsetvli pass
can be taught to fix this.