improve 'optRemoveRedundantZeroInits' (#50155)

improve 'optRemoveRedundantZeroInits' (#50155)

It covers cases like:
```
N006 ( 13, 12) [000019] -A-XG---R---              *  ASG       struct (copy)
N005 (  9,  9) [000018] n-----------              +--*  OBJ       struct<System.Threading.Tasks.ValueTask, 16>
N004 (  3,  5) [000017] ------------              |  \--*  ADDR      byref
N003 (  3,  4) [000014] D------N----              |     \--*  LCL_FLD   struct V03 tmp1         [+0] Fseq[_value]
N002 (  3,  2) [000015] ---XG-------              \--*  IND       struct
N001 (  1,  1) [000000] ------------                 \--*  LCL_VAR   byref  V00 this
```