Properly detect whether we're running on a buildbot.

pkg/unittest/lib/compact_vm_config.dart

Index: pkg/unittest/lib/compact_vm_config.dart
diff --git a/pkg/unittest/lib/compact_vm_config.dart b/pkg/unittest/lib/compact_vm_config.dart
index 97c120a3e08d95fac6afa97562900735590516e5..7724599a398c4624b8d0d54b4c9a7ebd8795a179 100644
--- a/pkg/unittest/lib/compact_vm_config.dart
+++ b/pkg/unittest/lib/compact_vm_config.dart
@@ -190,7 +190,7 @@ class CompactVMConfiguration extends VMConfiguration {
 void useCompactVMConfiguration() {
   // If the test is running on the Dart buildbots, we don't want to use this
   // config since it's output may not be what the bots expect.
-  if (Platform.environment.containsKey('BUILDBOT_BUILDERNAME')) {
+  if (Platform.environment['LOGNAME'] == 'chrome-bot') {

[Siggi Cherem (dart-lang), 2013/11/12 20:05:57]

does this work in windows/mac as well? IIRC, BUILDBOT_BUILDERNAME is used in all
platforms (true, as long as it's running annotated steps) Do you know which bots
don't use that?

[nweiz, 2013/11/12 20:11:11]

According to Rico, LOGNAME should work everywhere.

It looks like none of the VM bots except cross-arm-vm-linux-release use
annotated steps.

     return;
   }