Extract Function: Add test data

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

@@ -0,0 +1,17 @@
+// NEXT_SIBLING:
+fun foo(a: Int): Int {
+    var b: Int = 1
+
+    <selection>if (a > 0) {
+        b = b + 1
+    }
+    else if (a < 0) {
+        b--
+    }
+    else {
+        b = a
+    }
+    println(b)</selection>
+
+    return b
+}