Use a built-in marker class for Configure Kotlin action

This helps to get rid of the balloon which was shown in Kotlin project itself
because of the recent change where a source root was added to the module
'builtins', which doesn't have the class kotlin.jvm.internal.Intrinsics (the
'runtime.jvm' module does)

idea/idea-analysis/src/org/jetbrains/kotlin/idea/versions/KotlinRuntimeLibraryCoreUtil.java

@@ -28,7 +28,7 @@ import org.jetbrains.annotations.Nullable;
 
 public class KotlinRuntimeLibraryCoreUtil {
     private static final ImmutableList<String> CANDIDATE_CLASSES = ImmutableList.of(
-            "kotlin.jvm.internal.Intrinsics",
+            "kotlin.Unit",
 
             // For older versions
             "jet.runtime.Intrinsics"