Send idle notification on ASAN builder for proper tear down.

BUG=
R=yangguo@chromium.org

Review URL: https://codereview.chromium.org/300003005

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21498 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

tools/run-tests.py

@@ -256,6 +256,9 @@ def ProcessOptions(options):
   if options.gc_stress:
     options.extra_flags += GC_STRESS_FLAGS
 
+  if options.asan:
+    options.extra_flags.append("--send-idle-notification")
+
   if options.j == 0:
     options.j = multiprocessing.cpu_count()