Add a test to check correct references to a global variable that initially throws

tests/language/src/StaticInitializerTypeErrorTest.dart

+// 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.
+// VMOptions=--enable_type_checks
+
+
+int x = "milou";
+
+bool readXThrows() {
+  try {
+    var y = x;
+    return false;
+  } catch (var e) {
+    x = 5;  // Make sure we do not throw exception a second time.
+    return true;
+  }
+}
+
+main() {
+  int numExceptions = 0;
+  for (int i = 0; i < 8; i++) {
+    if (readXThrows()) {
+      numExceptions++;
+    }
+  }
+  // In checked mode throw only one exception.
+  Expect.equals(1, numExceptions);
+}