set explicit receiver kind properly for calls

compiler/testData/resolvedCalls/implicitReceiverIsThisObject.kt

@@ -0,0 +1,12 @@
+// !CALL: foo
+// !EXPLICIT_RECEIVER_KIND: NO_EXPLICIT_RECEIVER
+// !THIS_OBJECT: A
+// !RECEIVER_ARGUMENT: NO_RECEIVER
+
+class A {
+    fun foo() {}
+}
+
+fun A.bar() {
+    foo()
+}