Auto merge of #8236 - ehuss:no-panic-output, r=alexcrichton

Ignore broken console output in some situations.

If stdout or stderr is closed while Cargo is running, Cargo would panic in some situations (usually with EPIPE). For example, `cargo install --list | grep -q cargo-fuzz`, where `grep` will close stdout once it gets a match. This changes it so that Cargo will ignore output errors in most situations. Failure to output a regular build message still results in an error, which follows the behavior of some tools like `make`.

All output, including stdout, now goes through `Shell`.

Closes #5234