Auto merge of #3533 - jtgeibel:3519-dev-target, r=alexcrichton

Rename debug target to dev in build output

This renames the debug target to dev in the build output for non-release
builds.  This includes the output of commands such as `cargo build`,
`cargo test`, and `cargo doc`.

Closes #3519

diff --cc src/cargo/ops/cargo_rustc/job_queue.rs
Simple merge

diff --cc tests/build.rs
Simple merge

diff --cc tests/path.rs
Simple merge

diff --cc tests/test.rs
Simple merge