Add a leg_only test suite, and make sure to run it in our presubmit script.

tools/testing/test_case.py

 # Copyright (c) 2011, 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.
 
 """Common TestCase subclasses used to define a single test."""
 
 import os
 import tempfile
 
 import test
@@ skipping 46 matching lines @@
   def Cleanup(self):
     # TODO(ngeoffray): We run out of space on the build bots for these tests if
     # the temp directories are not removed right after running the test.
     if not self.context.keep_temporary_files:
       self.run_arch.Cleanup()
 
 
 class MultiTestCase(StandardTestCase):
   """Multiple test cases defined within a single *Test.dart file."""
 
-  def __init__(self, context, path, filename, kind, mode, arch, component):
+  def __init__(self, context, path, filename, kind, mode, arch, component,
+               vm_options = None):
     super(MultiTestCase, self).__init__(context, path, filename, mode, arch,
-                                        component)
+                                        component, vm_options)
     self.kind = kind
 
   def GetCommand(self):
     """Returns a commandline to execute to perform the test."""
     return self.run_arch.GetRunCommand(
         fatal_static_type_errors=(self.kind == 'static type error'))
 
   def IsNegative(self):
     """Determine if this is a negative test. by looking at @ directives.
 
@@ skipping 80 matching lines @@
             self.filename]
 
     return cmd
 
   def GetName(self):
     return self.path[-1]
 
   def Cleanup(self):
     if not self.context.keep_temporary_files:
       self.run_arch.Cleanup()