Extract Function: Support multiple output values

idea/testData/refactoring/extractFunction/controlFlow/outputValues/outputValueWithExpression.kt

@@ -0,0 +1,20 @@
+// WITH_RUNTIME
+// PARAM_TYPES: kotlin.Int
+// PARAM_TYPES: kotlin.Int
+// PARAM_DESCRIPTOR: value-parameter val a: kotlin.Int defined in foo
+// PARAM_DESCRIPTOR: var b: kotlin.Int defined in foo
+// SIBLING:
+fun foo(a: Int): Int {
+    var b: Int = 1
+
+    val t = <selection>if (a > 0) {
+        b += a
+        b
+    }
+    else {
+        a
+    }</selection>
+    println(b)
+
+    return t
+}