Move `rustc_passes::liveness` to MIR

[Centril]

Discussion in https://discordapp.com/channels/442252698964721669/443151243398086667/669220265821077535.

The liveness linting code in rustc_passes::liveness works on HIR using backwards dataflow. The code is quite complicated and imprecise. Moving it to rustc_mir::transform as a new pass could simplify the compiler, improve maintainability, as well as improve precision (e.g., sub-binding level precision for tuples, structs, and arrays).

cc @oli-obk cc @eddyb cc #65467 cc #51003

[eddyb]

Isn't this a duplicate of #51003? cc @nikomatsakis @pnkfelix

[nikomatsakis]

I believe it is, closing as duplicate of #51003.