Fix uses of throw/rethrow in tests.

tests/language/execute_finally10_test.dart

Index: tests/language/execute_finally10_test.dart
diff --git a/tests/language/execute_finally10_test.dart b/tests/language/execute_finally10_test.dart
index 4591908ee184525adb3bd48fbdf9bb8993d12218..74beb5a3c0001cc51da120fd8097e873c21ed192 100644
--- a/tests/language/execute_finally10_test.dart
+++ b/tests/language/execute_finally10_test.dart
@@ -6,7 +6,7 @@
 // block as a successor of a catch block that throws.
 
 import "package:expect/expect.dart";
- 
+
 class A {
   var field;
   start() {}
@@ -26,7 +26,7 @@ class B {
       // variable.
       runCompiler.toString();
       runCompiler.toString();
-      throw;
+      rethrow;
     } finally {
       totalCompileTime.stop();
     }