Enable vdiff test on validator bots

SConstruct

Index: SConstruct
diff --git a/SConstruct b/SConstruct
index 70019810b36d9087dedddfa2a3834ac02b689cf1..fff7d41e1a46b1434ee72c3a74e5b20bd4b5fcb1 100755
--- a/SConstruct
+++ b/SConstruct
@@ -336,6 +336,9 @@ def SetUpArgumentBits(env):
   #
   BitFromArgument(env, 'ncval_testing', default=False,
     desc='EXPERIMENTAL: Compile validator code for testing within enuminsts')
+  # Diff test comparing old validator with new R-DFA validator
+  BitFromArgument(env, 'validator_diff_tests', default=False,

[bradn, 2012/08/28 21:14:10]

So I think you should be able to drop this.
This is adding a boolean argument like:
validator_diff_tests=0 etc.
Whereas your actual target is just a normal test target (which should work fine
as you've added it to a new test suite).

[Brad Chen, 2012/08/28 22:09:42]

Done.

+    desc='Compare validator implementations')
 
   # PNaCl sanity checks
   if ((env.Bit('pnacl_generate_pexe') or env.Bit('use_sandboxed_translator'))
@@ -626,6 +629,8 @@ MAJOR_TEST_SUITES = set([
   'tsan_bot_tests',
   # Special testing environment for testing comparing x86 validators.
   'ncval_testing',
+  # Environment for validator difference testing
+  'validator_diff_tests',
 ])
 
 # These are the test suites we know exist, but aren't run on a regular basis.
@@ -1535,7 +1540,7 @@ TEST_EXTRA_ARGS = ['stdin', 'log_file',
                    'osenv', 'arch', 'subarch', 'exit_status', 'track_cmdtime',
                    'num_runs', 'process_output_single',
                    'process_output_combined', 'using_nacl_signal_handler',
-                   'declares_exit_status']
+                   'declares_exit_status', 'time_warning', 'time_error']
 
 TEST_TIME_THRESHOLD = {
     'small':   2,