use declared upper bounds in type inference (not just check them)

- simple cases supported
#KT-2856 fixed

compiler/testData/diagnostics/tests/inference/upperBounds/kt2856.kt

@@ -0,0 +1,20 @@
+//KT-2856 Fix the getOrElse signature to be able to return any supertype of V
+package d
+
+import java.util.HashMap
+
+public inline fun <K,V1, V: V1> Map<K,V>.getOrElse1(key: K, defaultValue: ()-> V1) : V1 {
+    if (this.containsKey(key)) {
+        return this.get(key) as V
+    } else {
+        return defaultValue()
+    }
+}
+
+fun main(args: Array<String>) {
+    val map = HashMap<Int, Int>()
+    println(map.getOrElse1(2, { null })) // Error
+}
+
+//from standard library
+fun println(<!UNUSED_PARAMETER!>message<!> : Any?) {}