Drop the default layout_test batch size for *SAN builds to 40.

BUG=427569
TBR=dpranke@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/726943002

git-svn-id: svn://svn.chromium.org/blink/trunk@185377 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/port/base.py

@@ -264,7 +264,7 @@ class Port(object):
             # ASAN/MSAN/TSAN use more memory than regular content_shell. Their
             # memory usage may also grow over time, up to a certain point.
             # Relaunching the driver periodically helps keep it under control.
-            return 50
+            return 40
         # The default is infinte batch size.
         return None