Make sure the struct field offset matches with that of parent during morphing

[kunalspathak]

#70170 exposed an issue because we started folding ADDR(LCL_FLD <original struct>) and removed the information about the fields.

There is a similar field access for parent struct and we think that the current field's zero-init is redundant and can be safely removed.

STMT00010 ( INL02 @ 0x000[E-] ... ??? ) <- INL01 @ 0x000[E-] <- INLRT @ 0x000[E-]
N003 (  5,  4) [000043] -A--G---R--                         *  ASG       int   
N002 (  3,  2) [000040] D---G--N---                         +--*  LCL_VAR   int   (AX) V07 tmp3         
N001 (  1,  1) [000041] -----------                         \--*  CNS_INT   int    0

***** BB01
STMT00009 ( INL01 @ 0x007[E-] ... ??? ) <- INLRT @ 0x000[E-]
N003 (  5,  6) [000035] -A--G---R--                         *  ASG       int   
N002 (  3,  4) [000029] D---G--N---                         +--*  LCL_FLD   int    V07 tmp3         [+4]
N001 (  1,  1) [000033] -----------                         \--*  CNS_INT   int    0

The fix is to before making it LCL_FLD make sure that the offsets are same too.

Fixes: #70791

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Issue Details

---

#70170 exposed an issue because we started folding ADDR(LCL_FLD <original struct>) and removed the information about the fields.

There is a similar field access for parent struct and we think that the current field's zero-init is redundant and can be safely removed.

STMT00010 ( INL02 @ 0x000[E-] ... ??? ) <- INL01 @ 0x000[E-] <- INLRT @ 0x000[E-]
N003 (  5,  4) [000043] -A--G---R--                         *  ASG       int   
N002 (  3,  2) [000040] D---G--N---                         +--*  LCL_VAR   int   (AX) V07 tmp3         
N001 (  1,  1) [000041] -----------                         \--*  CNS_INT   int    0

***** BB01
STMT00009 ( INL01 @ 0x007[E-] ... ??? ) <- INLRT @ 0x000[E-]
N003 (  5,  6) [000035] -A--G---R--                         *  ASG       int   
N002 (  3,  4) [000029] D---G--N---                         +--*  LCL_FLD   int    V07 tmp3         [+4]
N001 (  1,  1) [000033] -----------                         \--*  CNS_INT   int    0

The fix is to before making it LCL_FLD make sure that the offsets are same too.

Fixes: #70791

Author:	kunalspathak
Assignees:	-
Labels:	area-CodeGen-coreclr
Milestone:	-

[kunalspathak]

@dotnet/jit-contrib @SingleAccretion