Auto merge of rust-lang#3941 - noahmbright:unix_shims, r=oli-obk

Replace set_last_error with set_last_error_and_return

Took care of the simple patterns. Other patterns involved setting an error and then using `write_int` or setting metadata and returning -1. Unsure if those are in the scope of this change

Looks like this has conflicts with rust-lang#3779, so I can update when how to handle that is decided.

Part of rust-lang/miri#3930.

Author: bors