The mozharness_test job was using the wrong artifact path for native-engine.
Native-engine also enforces that artifact directories exist, so include some
mkdir calls to keep it happy.
MozReview-Commit-ID: Evw34gzzLev
When running an interactive worker (aka one-click loaner), developers have the option of setting
up the mozharness environment without running tests. When they do this, we should automatically
symlink the mach binary found in the tests.zip to their path. This way developers don't need to
go searching for $HOME/workspace/build/tests/mach to run their tests.
MozReview-Commit-ID: 1JKPYSsYKlN
