Add dartc junit tests to test.dart.

compiler/tests/dartc/dartc.status

Index: compiler/tests/dartc/dartc.status
diff --git a/compiler/tests/dartc/dartc.status b/compiler/tests/dartc/dartc.status
index bb6f62be02afb37bb4084493ac3c9e0b5d155d90..367516514f1d220f1db938aefc10cf126f1d7ad4 100644
--- a/compiler/tests/dartc/dartc.status
+++ b/compiler/tests/dartc/dartc.status
@@ -3,6 +3,13 @@
 # BSD-style license that can be found in the LICENSE file.
 prefix dartc
 
+# This directory creates a single java junit test, with name dartc/junit_tests.
+# This status file is only used to exclude all components except dartc
+# from performing the test, in the test.py script.
+
+# The individual file and directory exclusions are hardcoded into the scripts
+# client/tests/dartc/testcfg.py and client/tests/dartc/test_config.dart.
+# The component exclusions are hardcoded into test.dart.
 
 compiler/vm/*: Skip