[mono] Unify behavior of BulkMoveWithWriteBarrier with CoreCLR

[BrzVlad]

On mono, this method expects arguments as if it operates on full array elements, however, behind the scenes, it ends up multiplying element count with element size, operating without relying on alignment of array elements.

Remove this constraint so we can use implementation from #78450 also on mono.

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Issue Details

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On mono, this method expects arguments as if it operates on full array elements, however, behind the scenes, it ends up multiplying element count with element size, operating without relying on alignment of array elements.

Remove this constraint so we can use implementation from #78450 also on mono.

Author:	BrzVlad
Assignees:	BrzVlad
Labels:	area-GC-mono
Milestone:	8.0.0