Auto merge of #33622 - arielb1:elaborate-drops, r=nikomatsakis

[MIR] non-zeroing drop

This enables non-zeroing drop through stack flags for MIR.

Fixes #30380.
Fixes #5016.

diff --cc src/librustc/infer/mod.rs
Simple merge

diff --cc src/librustc/ty/mod.rs
Simple merge

diff --cc src/librustc/util/ppaux.rs
Simple merge

diff --cc src/librustc_driver/driver.rs
Simple merge

diff --cc src/librustc_metadata/decoder.rs
Simple merge

diff --cc src/librustc_trans/common.rs
Simple merge