Revert preparser duplicate detection.

test/preparser/testcfg.py

Index: test/preparser/testcfg.py
diff --git a/test/preparser/testcfg.py b/test/preparser/testcfg.py
index f80eeb5265c82a917be0f8b53ac2a736a3c46bda..39b62c396de4c304d5b4c33b60463a45f45d86ab 100644
--- a/test/preparser/testcfg.py
+++ b/test/preparser/testcfg.py
@@ -98,6 +98,7 @@ class PreparserTestConfiguration(test.TestConfiguration):
   def ParsePythonTestTemplates(self, result, filename,
                                executable, current_path, mode):
     pathname = join(self.root, filename + ".pyt")
+    source = open(pathname).read();
     def Test(name, source, expectation):
       throws = None
       if (expectation is not None):
@@ -117,7 +118,8 @@ class PreparserTestConfiguration(test.TestConfiguration):
           testsource = testsource.replace("$"+key, replacement[key]);
         Test(testname, testsource, expectation)
       return MkTest
-    execfile(pathname, {"Test": Test, "Template": Template})
+    eval(compile(source, pathname, "exec"),
+         {"Test": Test, "Template": Template}, {})
 
   def ListTests(self, current_path, path, mode, variant_flags):
     executable = join('obj', 'preparser', mode, 'preparser')
@@ -141,7 +143,7 @@ class PreparserTestConfiguration(test.TestConfiguration):
     filenames.sort()
     for file in filenames:
       # Each file as a python source file to be executed in a specially
-      # created environment (defining the Template and Test functions)
+      # perparsed environment (defining the Template and Test functions)
       self.ParsePythonTestTemplates(result, file,
                                     executable, current_path, mode)
     return result