Debugger: fix evaluate expression for traits

idea/testData/debugger/tinyApp/src/evaluate/singleBreakpoint/extractThisInTrait.kt

@@ -0,0 +1,23 @@
+package extractThisInTrait
+
+fun main(args: Array<String>) {
+    TImpl().foo()
+}
+
+trait T {
+    fun foo() {
+        //Breakpoint!
+        val a = 1
+    }
+
+    val prop: Int
+        get() = 1
+}
+
+class TImpl(): T
+
+// EXPRESSION: prop
+// RESULT: 1: I
+
+// EXPRESSION: this.prop
+// RESULT: 1: I