Update iOS bots to use the 8.3 SDK

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

Index: ios/build/bots/chromium.mac/iOS_Simulator_(dbg).json
diff --git a/ios/build/bots/chromium.mac/iOS_Simulator_(dbg).json b/ios/build/bots/chromium.mac/iOS_Simulator_(dbg).json
index 81e7322b773b40709fee4286bb127447d0cd4ab3..3d9e9a25bf51050ceca30ec81318b9a451b9a981 100644
--- a/ios/build/bots/chromium.mac/iOS_Simulator_(dbg).json
+++ b/ios/build/bots/chromium.mac/iOS_Simulator_(dbg).json
@@ -3,26 +3,26 @@
     "smut"
   ],
   "comments": [
-    "Tests for 32- and 64-bit iOS 8.2 iPhone simulators."
+    "Tests for 32- and 64-bit iOS 8.3 iPhone simulators."
   ],
-  "xcode version": "6.2",
+  "xcode version": "6.3",
   "GYP_DEFINES": {
     "chromium_ios_signing": "0",
     "target_subarch": "both"
   },
   "compiler": "xcodebuild",
   "configuration": "Debug",
-  "sdk": "iphonesimulator8.2",
+  "sdk": "iphonesimulator8.3",
   "tests": [
     {
       "include": "common_tests.json",
       "device type": "iPhone 5",
-      "os": "8.2"
+      "os": "8.3"
     },
     {
       "include": "common_tests.json",
       "device type": "iPhone 5s",
-      "os": "8.2"
+      "os": "8.3"
     }
   ]
 }