[iOS/GN] Enable running tests on simulator.

ios/build/bots/tryserver.chromium.mac/ios_dbg_simulator_gn.json

Index: ios/build/bots/tryserver.chromium.mac/ios_dbg_simulator_gn.json
diff --git a/ios/build/bots/tryserver.chromium.mac/ios_dbg_simulator_gn.json b/ios/build/bots/tryserver.chromium.mac/ios_dbg_simulator_gn.json
index 410ed63d676c33ddfaeaf3a17d699ef61dcfcde4..a104d01c616ac6ab9406a0381c3afe8a22a6ed45 100644
--- a/ios/build/bots/tryserver.chromium.mac/ios_dbg_simulator_gn.json
+++ b/ios/build/bots/tryserver.chromium.mac/ios_dbg_simulator_gn.json
@@ -9,17 +9,30 @@
   "xcode version": "7.0",
   "GYP_DEFINES": {
     "chromium_ios_signing": "0",
-    "target_subarch": "both",
+    "gomadir": "$(goma_dir)",
     "use_goma": "1"
   },
   "gn_args": [
     "target_os=\"ios\"",
-    "use_goma=true"
+    "target_cpu=\"x64\"",
+    "is_debug=true",
+    "use_goma=true",
+    "goma_dir=\"$(goma_dir)\""
   ],
   "mb_type": "gn",
   "compiler": "ninja",
   "configuration": "Debug",
   "sdk": "iphonesimulator9.0",
   "tests": [
+    {
+      "include": "common_tests.json",
+      "device type": "iPhone 5s",
+      "os": "9.0"
+    },
+    {
+      "include": "common_tests.json",
+      "device type": "iPad Air",
+      "os": "9.0"
+    }
   ]
 }