Change test to use unittest for integration into treehugger

Rename test.py to slang_test.py
Change tests to be run under unittest rather than manually
Add run_slang_tests.sh shell script to integrate into treehugger

Test: python slang_test.py (failing test cases are reported correctly)

Change-Id: Ida597a23664d638dd32d7619f014a3dd6dd13205
(cherry picked from commit d83b36e15d1ba33e644ad75f1168aed4c9df2646)
3 files changed