Merge "Move TetheringTests to presubmit"

packages/Tethering/TEST_MAPPING

 {
-  "postsubmit": [
+  "presubmit": [
     {
       "name": "TetheringTests"
     }
+  ],
+  "postsubmit": [
+    {
+      "name": "TetheringIntegrationTests"
+    }
   ]
 }