Auto merge of #7162 - yaahallo:clippyargs, r=ehuss

reimplement arg passthrough for clippy-driver

Prior to this change, the old cargo subcommand version of `cargo clippy`
had a feature to pass trailing args down to clippy-driver but when this
the subcommand was reimplemented inside of cargo this feature was left
out accidentally.

This change readds the feature to to capture all args after a trailing
-- and forward them down to clippy-driver via an env variable.

diff --cc src/cargo/core/compiler/compilation.rs
Simple merge