Don't unmap ports in host_driven/test_case.py.

The sync tests failure seems to have to do with port unmapping. Not unmapping
ports let most of the sync tests pass (only 2 failures remain for an unrelated
reason apparently).
Note that port unmapping was added to avoid exceeding the file descriptor limit
in net_unittests since each test server was listening on a different port. The
sync tests use a server always listening on a same port so unmapping the port
is not strictly needed.

BUG=313809

Review URL: https://codereview.chromium.org/106533002

git-svn-id: http://src.chromium.org/svn/trunk/src/build@239467 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

android/pylib/host_driven/test_case.py

@@ -73,8 +73,7 @@ class HostDrivenTestCase(object):
       self.ports_to_forward = ports_to_forward
 
   def TearDown(self):
-    if self.ports_to_forward:
-      forwarder.Forwarder.UnmapAllDevicePorts(self.adb)
+    pass
 
   # TODO(craigdh): Remove GetOutDir once references have been removed
   # downstream.
@@ -92,8 +91,6 @@ class HostDrivenTestCase(object):
             '--End Full HostForwarder log\n' % forwarder.Forwarder.GetHostLog())
 
   def __StartForwarder(self):
-    # Unmap any left over from previous test.
-    forwarder.Forwarder.UnmapAllDevicePorts(self.adb)
     logging.warning('Forwarding %s %s', self.ports_to_forward,
                     self.has_forwarded_ports)
     if self.ports_to_forward and not self.has_forwarded_ports: