Auto merge of #120692 - Nadrieril:move-column-analysis-to-placeinfo, r=compiler-errors

pattern_analysis: Move constructor selection logic to `PlaceInfo`

This is a small refactor PR. There was a dense bit of constructor-related logic in `compute_exhaustiveness_and_usefulness`. I'm moving it out into a `PlaceInfo` method to make it easier to follow both separately. I also have plans that will complicate it further so it's good that it's somewhat encapsulated.

r? `@compiler-errors`

Author: bors