Build: Remove faulty iOS 10-11 devices from browserstack matrix

* Times out after 1 hour.
* No trace of it in the BrowserStack REST API (/workers).
* In the online dashboard for Automate, allegedly still running after
  7 days.

Author: Krinkle

build/browserstack-full.json

@@ -42,19 +42,7 @@
       "os_version": "10.0"
     },
     {
-      "device": "iPhone 7",
-      "real_mobile": true,
-      "os": "ios",
-      "os_version": "10"
-    },
-    {
-      "device": "iPhone SE",
-      "real_mobile": true,
-      "os": "ios",
-      "os_version": "11"
-    },
-    {
-      "device": "iPhone XR",
+      "device": "iPhone 8",
       "real_mobile": true,
       "os": "ios",
       "os_version": "12"

build/browserstack-quick.json

@@ -17,12 +17,6 @@
       "real_mobile": true,
       "os": "android",
       "os_version": "10.0"
-    },
-    {
-      "device": "iPhone SE",
-      "real_mobile": true,
-      "os": "ios",
-      "os_version": "11"
     }
   ]
 }