JIT: Investigate relationship of basic block's `bbCodeOffs` + `bbCodeOffsEnd` and its statements' `DebugInfo`

[TIHan]

When looking at issue #99543 , a fair amount of time was spent trying to understand how the relationship of a basic blocks' IL offsets, bbCodeOffs/bbCodeOffsEnd, correspond to the blocks' statements' DebugInfo they contain.

Items to investigate:

• What is not clear is what should happen to the basic blocks' IL offsets if the statements they contain are modified/transformed (during a Debug compilation).

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[JulieLeeMSFT]

Good point. I think we are not consistent in maintaining IL offset when merging/spliting basic blocks.

[amanasifkhalid]

This isn't critical to .NET 10 -- pushing this out