Fix problem with missing handleResult call

At first we try to resolve 'handleResult' just as last expression
in a lambda is first argument, then if results are unsuccessful
try resolve 'handleResult' with fake Unit expression

 #KT-12969 Fixed

compiler/testData/codegen/box/coroutines/handleResultNonUnitExpression.kt

@@ -0,0 +1,28 @@
+class Controller {
+    var isCompleted = false
+    suspend fun suspendHere(x: Continuation<String>) {
+        x.resume("OK")
+    }
+
+    operator fun handleResult(x: Unit, y: Continuation<Nothing>) {
+        isCompleted = true
+    }
+}
+
+fun builder(coroutine c: Controller.() -> Continuation<Unit>) {
+    val controller = Controller()
+    c(controller).resume(Unit)
+    if (!controller.isCompleted) throw java.lang.RuntimeException("fail")
+}
+
+fun box(): String {
+    builder {
+        "OK"
+    }
+
+    builder {
+        suspendHere()
+    }
+
+    return "OK"
+}