[iOS/GN] Enable running tests on simulator.

ios/build/bots/chromium.mac/iOS_Simulator_GN_(dbg).json

Index: ios/build/bots/chromium.mac/iOS_Simulator_GN_(dbg).json
diff --git a/ios/build/bots/chromium.mac/iOS_Simulator_GN_(dbg).json b/ios/build/bots/chromium.mac/iOS_Simulator_GN_(dbg).json
index 753e42462f609179f535bc30d95951413bbd500e..e62ed39726714cac716f1b742c3a5c0774791832 100644
--- a/ios/build/bots/chromium.mac/iOS_Simulator_GN_(dbg).json
+++ b/ios/build/bots/chromium.mac/iOS_Simulator_GN_(dbg).json
@@ -9,12 +9,15 @@
   "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",
@@ -22,5 +25,15 @@
   "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"
+    }
   ]
 }