Whitelist mb files for 'mb analyze', fix Android GN test targets.

testing/buildbot/chromium.linux.json

 {
   "Android GN": {
     "additional_compile_targets": [
       "chrome_shell_apk"
     ],
-    "gtest_tests": [
-      {
-        "test": "base_unittests"
-      }
-    ]
+    "gtest_tests": []
   },
   "Android Tests": {
     "scripts": [
       {
         "name": "webview_licenses",
         "script": "webview_licenses.py"
       }
     ]
   },
   "Android Tests (dbg)": {
@@ skipping 840 matching lines @@
       }
     ],
     "scripts": [
       {
         "name": "nacl_integration",
         "script": "nacl_integration.py"
       }
     ]
   }
 }