Disable 64-bit tests on 32-bit devices.

Change-Id: Id1217771423f4db9266d1cb1218478fb9039a612
diff --git a/utils/python/controllers/android_device.py b/utils/python/controllers/android_device.py
index 03d48c7..307b690 100644
--- a/utils/python/controllers/android_device.py
+++ b/utils/python/controllers/android_device.py
@@ -434,6 +434,12 @@
         return cpu_abi
 
     @property
+    def is64Bit(self):
+        """True if device is 64 bit."""
+        out = self.adb.shell('uname -m')
+        return "64" in out
+
+    @property
     def isAdbLogcatOn(self):
         """Whether there is an ongoing adb logcat collection.
         """