Add a cross scheme link test.

2 jobs for cross_scheme_links in 1 minute and 2 seconds (queued for 2 seconds)
Name Stage Failure
build:redox Build
warning: build failed, waiting for other jobs to finish...
error: aborting due to 9 previous errors

Some errors have detailed explanations: E0432, E0658.
For more information about an error, try `rustc --explain E0432`.
error: build failed
redoxer cargo: exit status: 101
Cleaning up project directory and file based variables
ERROR: Job failed: exit code 1