Vector strided operations access the first memory element at the base address,
and then access subsequent elements at address increments given by the byte
offset contained in the x register specified by rs2.
Vector unit-stride operations access elements stored contiguously in memory
starting from the base effective address. It can been seen as a special
case of strided operations.
Backports 751538d5da557e5c10e5045c2d27639580ea54a7
vsetvl and vsetvli are two configure instructions for vl, vtype. TB flags
should update after configure instructions. The (ill, lmul, sew ) of vtype
and the bit of (VSTART == 0 && VL == VLMAX) will be placed within tb_flags.
Backports 2b7168fc43fb270fb89e1dddc17ef54714712f3a from qemu