Control-Flow: Fix pseudocode generation for combined get/set and invoke conventions

#KT-4462 Fixed
 #KT-4681 Fixed

compiler/testData/cfg/conventions/complexAssignmentWithGetSetViaVar.kt

@@ -0,0 +1,13 @@
+class Bar {
+    fun invoke(x: Int): Int = x
+    fun invoke(x: Int, y: Int) {}
+}
+
+class Foo {
+    val get: Bar = Bar()
+    val set: Bar = Bar()
+}
+
+fun test(foo: Foo) {
+    foo[1] += 2
+}