DebugInfo: Couple of recent size underflow issues

Vitaly for D89838/PR47927 which caused some recent “size underflow” assertions
Adrian for D70508 as the original author of the assertion in 2019

There’s been a couple of recent bugs reported with the “size underflow” assertion firing that might be related to Vitaly’s recent work (one was reported before that was reverted, but one I /think/ I’ve reproduced since the revert) that might be of interest (or perhaps you folks can pull in folks who are currently working on this sort of thing): and PR52584

Probably +Vedant Kumar instead of Vitaly?

Oh, sorry, yes - I see you (Vitaly) reported the crash, but didn’t author the patch.