Constructors represented "as in Java".

TODO: extract nested initializers somehow.

compiler/testData/ir/irText/classes/superCalls.kt

@@ -0,0 +1,14 @@
+open class Base {
+    open fun foo() {}
+
+    open val bar: String = ""
+}
+
+class Derived : Base() {
+    override fun foo() {
+        super.foo()
+    }
+
+    override val bar: String
+        get() = super.bar
+}