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

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

 # Copyright (C) 2010 Google Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 # copyright notice, this list of conditions and the following disclaimer
@@ skipping 246 matching lines @@
         if self._pretty_patch_available is None:
             self._pretty_patch_available = self.check_pretty_patch(logging=False)
         return self._pretty_patch_available
 
     def default_batch_size(self):
         """Return the default batch size to use for this port."""
         if self.get_option('enable_sanitizer'):
             # 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
 
     def default_child_processes(self):
         """Return the number of drivers to use for this port."""
         if self.get_option('enable_sanitizer'):
             # ASAN/MSAN/TSAN are more cpu- and memory- intensive than regular
             # content_shell, and so we need to run fewer of them in parallel.
             return max(int(self._executive.cpu_count() * 0.75), 1)
         return self._executive.cpu_count()
@@ skipping 1460 matching lines @@
 
 class PhysicalTestSuite(object):
     def __init__(self, base, args):
         self.name = base
         self.base = base
         self.args = args
         self.tests = set()
 
     def __repr__(self):
         return "PhysicalTestSuite('%s', '%s', %s)" % (self.name, self.base, self.args)