Fix issue 21795.

tests/language/regress_21795_test.dart

+// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// Regression test for issue 21795.
+
+foo(t) {
+  try {
+    if (t == 123) throw 42;
+  } finally { }
+}
+
+bar() {
+  try {
+    return 42;
+  } finally { }
+}
+
+
+class A {
+  test(t) {
+    try {
+      foo(t);
+    } finally {
+      if (t == 0) {
+        try {
+        } catch (err, st) {
+        }
+      }
+    }
+  }
+}
+
+
+main() {
+  var a = new A();
+  for (var i=0; i<10000; ++i) a.test(0);
+  try {
+    a.test(123);
+  } catch (e, s) {
+    if (s.toString().indexOf("foo") == -1) {
+      print(s);
+      throw "Expected foo in stacktrace!";
+    }
+  }
+}