complete type inference(*) for variable as function call as well

* dependent on expected type
+ get rid of instanceof ResolvedCallImpl check

compiler/testData/diagnostics/tests/inference/nestedCalls/completeNestedForVariableAsFunctionCall.kt

@@ -0,0 +1,16 @@
+package j
+
+trait MyFunc<T> {}
+
+class A(val b: B) {
+}
+
+class B {
+    fun <T> invoke(<!UNUSED_PARAMETER!>f<!>: (T) -> T): MyFunc<T> = throw Exception()
+}
+
+fun id<R>(r: R) = r
+
+fun foo(a: A) {
+    val <!UNUSED_VARIABLE!>r<!> : MyFunc<Int> = id (a.b { x -> x + 14 })
+}