Exclude ClientSocketPoolBaseTest.DisableCleanupTimer under DrMemory

This is a hang that slows down the bot and the test looks very sensitive to
timing.  I'm not interested in fully investigating this failure, and I'd like
the bot to cycle faster sooner.

R=bruening@chromium.org
BUG=105762

Review URL: http://codereview.chromium.org/8735005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@112198 0039d316-1c4b-4281-b951-d872f2087c98

tools/valgrind/gtest_exclude/net_unittests.gtest-drmemory_win32.txt

@@ -12,3 +12,7 @@ ProxyResolverV8Test.*
 
 # Slow
 CookieMonsterTest.GarbageCollectionTriggers
+
+# Hangs only when built in release mode.
+# http://crbug.com/105762
+ClientSocketPoolBaseTest.DisableCleanupTimer