Auto merge of #42369 - RalfJung:drop-glue, r=eddyb
Auto merge of #42369 - RalfJung:drop-glue, r=eddyb

array drop glue: avoid using out-of-bounds index lvalues

Avoid using out-of-bounds index lvalues. Miri doesn't like them, and they seem fishy in general.
Instead, use a pointer cast to compute the address of the beginning, and Offset to compute the end.

Cc @arielb1 @nagisa

graydon/rust,GBGamer/rust,aidancully/rust,GBGamer/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust,GBGamer/rust,aidancully/rust,graydon/rust,GBGamer/rust,aidancully/rust,GBGamer/rust,graydon/rust,aidancully/rust,GBGamer/rust,aidancully/rust,GBGamer/rust,GBGamer/rust