Auto merge of #111696 - lukas-code:offset-of-erase-regions-harder, r=compiler-errors

don't skip inference for type in `offset_of!`

Fixes rust-lang/rust#111678 by no longer skipping inference on the type in `offset_of!`. Simply erasing the regions the during writeback isn't enough and can cause ICEs. A test case for this is included.

This reverts rust-lang/rust#111661, because it becomes redundant, since inference already erases the regions.

Author: bors