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

build/android/pylib/host_driven/test_case.py

Index: build/android/pylib/host_driven/test_case.py
diff --git a/build/android/pylib/host_driven/test_case.py b/build/android/pylib/host_driven/test_case.py
index 20a8fd14bae500474bca608af4442c80dcb9aae4..8ff94083a395f7595357c96029838a39a99c74d9 100644
--- a/build/android/pylib/host_driven/test_case.py
+++ b/build/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: