Quick Fixes: Implement quickfix for missing library

idea/testData/quickfix/libraries/junit.kt

@@ -0,0 +1,14 @@
+// "Add 'JUnit4' to classpath" "true"
+// ERROR: Unresolved reference: Before
+// ERROR: Unresolved reference: junit
+// UNCONFIGURE_LIBRARY: JUnit4
+package some
+
+import org.<caret>junit.Before
+
+open class KBase {
+    @Before
+    fun setUp() {
+        throw UnsupportedOperationException()
+    }
+}