Auto merge of #54509 - matthewjasper:better-drop-access, r=pnkfelix

[NLL] Rework checking for borrows conflicting with drops

Previously, we would split the drop access into multiple checks for each
field of a struct/tuple/closure and through `Box` dereferences. This
changes this to check if the borrow is accessed by the drop in
`places_conflict`.

We also now handle enums containing `Drop` types.

Closes #53569

r? @nikomatsakis
cc @pnkfelix