Shard dart2js unit tests as well.

dart/tools/bots/compiler.py

Index: dart/tools/bots/compiler.py
diff --git a/dart/tools/bots/compiler.py b/dart/tools/bots/compiler.py
index 3cfd6e54c27a11ddfcc7de3c66076517c4e3aa84..72cf2e69a0cee959c24a6108c971b0a03ac0ffe7 100644
--- a/dart/tools/bots/compiler.py
+++ b/dart/tools/bots/compiler.py
@@ -219,9 +219,11 @@ def TestCompiler(runtime, mode, system, flags, is_buildbot, test_set):
     # The dart2js compiler isn't self-hosted (yet) so we run its
     # unit tests on the VM. We avoid doing this on the builders
     # that run the browser tests to cut down on the cycle time.
+    unit_test_flags = [flag for flag in flags if flag.startswith('--shard')]
+    # Run the unit tests in checked mode (the VM's checked mode).

[ricow1, 2013/05/21 10:26:24]

We already do this on the checked mode bots, why not remove this? (i.e., we pass
in the --checked flag twice on the checked mode bots and once on the regular
bots)

[ahe, 2013/05/21 11:41:33]

We are not passing the "--checked" flag twice.  All flags but the shard flags
are being removed on line 222.

These are dart2js *unit* tests, and they are not being compiled with dart2js. 
Instead they are running directly on the Dart VM, and we should not be passing
dart2js flags to the Dart VM.

[kustermann, 2013/05/21 11:44:57]

In addition to that, test_options.dart will throw if we pass the same flag
multiple times AFAIK.

+    unit_test_flags.append('--checked')
     TestStep("dart2js_unit", mode, system, 'none', 'vm', ['dart2js'],
-             # Run the unit tests in checked mode (the VM's checked mode).
-             ['--checked'])
+             unit_test_flags)
 
   if system.startswith('win') and runtime.startswith('ie10'):
     TestStep("dart2js", mode, system, 'dart2js', runtime, ['html'], flags)