Fix control flow graph in the presence of aborting instructions in a try/catch/finally.

tests/language/try_catch5_test.dart

Index: tests/language/try_catch5_test.dart
===================================================================
--- tests/language/try_catch5_test.dart	(revision 0)
+++ tests/language/try_catch5_test.dart	(revision 0)
@@ -0,0 +1,33 @@
+// Copyright (c) 2012, 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.
+// Check that our SSA graph does have the try body a predecessor of a
+// try/finally.
+
+var a;
+
+foo1() {
+  var b = false;
+  var entered = false;
+  while (true) {
+    if (entered) return b;
+    b = 8 == a; // This expression should not be GVN'ed.
+    try {
+      try {
+        a = 8;
+        return;
+      } finally {
+        b = 8 == a;
+        entered = true;
+        continue;
+      }
+    } finally {
+      continue;
+    }
+  }
+}
+
+main() {
+  a = 0;
+  Expect.isTrue(foo1());
+}