Deal with absence of js library. fix K2JSMessagingTest

compiler/cli/src/org/jetbrains/jet/cli/js/K2JSCompiler.java

@@ -42,6 +42,7 @@ import org.jetbrains.k2js.facade.K2JSTranslator;
 import org.jetbrains.k2js.facade.MainCallParameters;
 
 import java.io.File;
+import java.util.Arrays;
 import java.util.List;
 
 import static org.jetbrains.jet.cli.common.messages.CompilerMessageLocation.NO_LOCATION;
@@ -151,6 +152,6 @@ public class K2JSCompiler extends CLICompiler<K2JSCompilerArguments, K2JSCompile
             // lets discover the JS library definitions on the classpath
             return new ClassPathLibraryDefintionsConfig(project, moduleId, ecmaVersion);
         }
-        return new LibrarySourcesConfig(project, moduleId, arguments.libraryFiles, ecmaVersion);
+        return new LibrarySourcesConfig(project, moduleId, Arrays.asList(arguments.libraryFiles), ecmaVersion);
     }
 }