Refactor the tools/test.py script and related testcfg.py files....

test/mozilla/testcfg.py

Index: test/mozilla/testcfg.py
===================================================================
--- test/mozilla/testcfg.py	(revision 5302)
+++ test/mozilla/testcfg.py	(working copy)
@@ -57,9 +57,8 @@
 class MozillaTestCase(test.TestCase):
 
   def __init__(self, filename, path, context, root, mode, framework):
-    super(MozillaTestCase, self).__init__(context, path)
+    super(MozillaTestCase, self).__init__(context, path, mode)
     self.filename = filename
-    self.mode = mode
     self.framework = framework
     self.root = root
 
@@ -75,8 +74,8 @@
     return 'FAILED!' in output.stdout
 
   def GetCommand(self):
-    result = [self.context.GetVm(self.mode), '--expose-gc',
-              join(self.root, 'mozilla-shell-emulation.js')]
+    result = self.context.GetVmCommand(self, self.mode) + \
+       [ '--expose-gc', join(self.root, 'mozilla-shell-emulation.js') ]
     result += self.framework
     result.append(self.filename)
     return result