add ultra-light classes/members that work without backend in simple cases

compiler/testData/asJava/ultraLightClasses/constructors.kt

@@ -0,0 +1,8 @@
+
+class TestConstructor private constructor(p: Int = 1)
+class A(vararg a: Int, f: () -> Unit) {}
+
+class B {
+    @Deprecated("", level = DeprecationLevel.HIDDEN)
+    constructor()
+}