Added file to test library used in LibrariesWith[out]SourcesTests.

idea/testData/libraries/library/extra.kt

@@ -0,0 +1,4 @@
+package testData.libraries
+
+public fun func(str : String) {
+}

idea/testData/libraries/library/main.kt

@@ -1,7 +1,5 @@
 package testData.libraries
 
-import java.util.*
-
 public trait SimpleTrait {
 }