add test case

Author: liufengyun

compiler/test-resources/repl/i4217

@@ -0,0 +1,7 @@
+scala> def foo(x: Option[Int]) = x match { case None => }
+1 |def foo(x: Option[Int]) = x match { case None => }
+  |                          ^
+  |                          match may not be exhaustive.
+  |
+  |                          It would fail on pattern case: Some(_)
+def foo(x: Option[Int]): Unit