Fix for KT-9140: Default parameters are passed as nulls when using indexing [ ] invocation

#KT-9140 Fixed

compiler/testData/codegen/box/defaultArguments/convention/incWithDefaultInGetter.kt

@@ -0,0 +1,26 @@
+var inc: String = ""
+
+class X {
+    var result: String = "fail"
+
+    operator fun get(name: String, type: String = "none") = name + inc + type
+
+    operator fun set(name: String, s: String) {
+        result = name + s;
+    }
+}
+
+operator fun String.inc(): String {
+    inc = this + "1"
+    return this + "1"
+}
+
+fun box(): String {
+    var x = X()
+    val res = ++x["a"]
+    if (x.result != "aanone1") return "fail 1: ${x.result}"
+
+    if (res != "aanone1none") return "fail 2: ${res}"
+
+    return "OK"
+}