JIT: Fall back to a canonical SIMD handle in gtGetStructHandleForSimdOrHW

[jakobbotsch]

Fix #80239

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Issue Details

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Fix #80239

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

[tannergooding]

@jakobbotsch looks like some path is passing in a non simdType and that's causing an unreached to be hit.

[jakobbotsch]

We call gtGetStructHandleForSimdOrHW on

N002 (  2,  2)              [000001] ---XG------ >>>                     ▌  HWINTRINSIC struct int LoadPairScalarVector64 <l:$183, c:$182>
N001 (  1,  1)              [000000] -----------                         └──▌  LCL_VAR   long   V00 arg0         u:1 (last use) $80

from gtGetStructHandleIfPresent. I'll make gtGetStructHandleIfPresent return NO_CLASS_HANDLE for non-SIMD HW intrinsics.