Throw a runtime error when trying to call a constructor of a class that could not be resolved.

tests/language/call_constructor_on_unresolvable_class_test.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.
+
+// Check that calling a constructor of a class that cannot be resolved causes
+// a runtime error.
+
+#import('dart:math');
+
+never() {
+  Random r = new Random();
+  int r1 = r.nextInt(1000);
+  int r2 = r.nextInt(1000);
+  int r3 = r.nextInt(1000);
+  return (r1 > r3) && (r2 > r3) && (r3 > r1 + r2);
+}
+
+main() {
+  if (never()) {
+    // These should not produce errors because the calls are never executed.
+    new A();         /// 01: static type warning
+    new A.foo();     /// 02: static type warning
+    new library.A(); /// 03: static type warning
+  }
+
+  new A();         /// 04: runtime error
+  new A.foo();     /// 05: runtime error
+  new library.A(); /// 06: runtime error
+
+  var ex;                            /// 07: static type warning
+  try {                              /// 07: continued
+    new A();                         /// 07: continued
+  } catch (e) {                      /// 07: continued
+    ex = e;                          /// 07: continued
+  }                                  /// 07: continued
+  Expect.isTrue(ex is RuntimeError); /// 07: continued
+}