Constructors represented "as in Java".

TODO: extract nested initializers somehow.

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

@@ -0,0 +1,19 @@
+interface ILeft {
+    fun foo() {}
+    val bar: Int get() = 1
+}
+
+interface IRight {
+    fun foo() {}
+    val bar: Int get() = 2
+}
+
+class CBoth : ILeft, IRight {
+    override fun foo() {
+        super<ILeft>.foo()
+        super<IRight>.foo()
+    }
+
+    override val bar: Int
+        get() = super<ILeft>.bar + super<IRight>.bar
+}