Background compilation work:

tests/language/vm/optimized_stacktrace_test.dart

Index: tests/language/vm/optimized_stacktrace_test.dart
diff --git a/tests/language/vm/optimized_stacktrace_test.dart b/tests/language/vm/optimized_stacktrace_test.dart
index c5f98c984cad620232c8a8cbf1b333e70bcccb9f..3ad73f162130c8ff50b28a8c0e70378f2a669709 100644
--- a/tests/language/vm/optimized_stacktrace_test.dart
+++ b/tests/language/vm/optimized_stacktrace_test.dart
@@ -1,7 +1,7 @@
 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
-// VMOptions=--stacktrace-every=3 --optimization-counter-threshold=10 --enable-inlining-annotations
+// VMOptions=--stacktrace-every=3 --optimization-counter-threshold=10 --enable-inlining-annotations --no-background-compilation
 
 // Test generating stacktraces with inlining and deferred code.
 // Regression test for issue dartbug.com/22331