Migrate chromium.webrtc.fyi ios bot to ios11

Chrome iOS stopped supporting ios10.

Bug: 904393
Change-Id: I89e9cfe5cc27e8ef94feb5e8b404e1fc8d8264d7
Reviewed-on: https://chromium-review.googlesource.com/c/1329968
Commit-Queue: Olivier Robin <olivierrobin@chromium.org>
Reviewed-by: Patrik Höglund <phoglund@chromium.org>
Reviewed-by: Justin Cohen <justincohen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#607380}

ios/build/bots/chromium.webrtc.fyi/WebRTC Chromium FYI ios-device.json

 {
   "comments": [
-    "Builder for 32-bit devices.",
+    "Builder for 64-bit devices.",
     "Build is performed with gn+ninja."
   ],
   "xcode build version": "10b61",
   "gn_args": [
-    "additional_target_cpus=[ \"arm64\" ]",
     "goma_dir=\"$(goma_dir)\"",
     "ios_enable_code_signing=false",
     "is_component_build=false",
     "is_debug=false",
-    "target_cpu=\"arm\"",
-    "ios_deployment_target=\"10.0\"",
+    "target_cpu=\"arm64\"",
     "target_os=\"ios\"",
     "use_goma=true"
   ],

ios/build/bots/chromium.webrtc.fyi/WebRTC Chromium FYI ios-simulator.json

 {
   "comments": [
-    "Runs tests on @3x, @2x, 64-bit, 32-bit, phone, tablet, iOS 10, and iOS 9."
+    "Runs tests on @3x, @2x, 64-bit phone, tablet, iOS 11."
   ],
   "xcode build version": "10b61",
   "gn_args": [
-    "additional_target_cpus=[\"x86\"]",
     "goma_dir=\"$(goma_dir)\"",
     "ios_enable_code_signing=false",
     "is_component_build=false",
     "is_debug=true",
     "symbol_level=1",
     "target_cpu=\"x64\"",
-    "ios_deployment_target=\"10.0\"",
     "target_os=\"ios\"",
     "use_goma=true"
   ],
@@ -24,42 +22,17 @@
     {
       "include": "common_tests.json",
       "device type": "iPhone 6s Plus",
-      "os": "10.0"
+      "os": "11.4"
     },
     {
       "include": "common_tests.json",
       "device type": "iPhone 6s",
-      "os": "10.0"
-    },
-    {
-      "include": "common_tests.json",
-      "device type": "iPhone 5",
-      "os": "10.0"
-    },
-    {
-      "include": "common_tests.json",
-      "device type": "iPad Air 2",
-      "os": "10.0"
-    },
-    {
-      "include": "common_tests.json",
-      "device type": "iPad Retina",
-      "os": "10.0"
-    },
-    {
-      "include": "common_tests.json",
-      "device type": "iPhone 5",
-      "comments": [
-        "This still relies on system iOS 9.0 legacy simulators,",
-        "since Xcode 8.0 doesn't provide it. But our test runner",
-        "doesn't support Xcode 7.0 anymore..."
-      ],
-      "os": "9.0"
+      "os": "11.4"
     },
     {
       "include": "common_tests.json",
       "device type": "iPad Air 2",
-      "os": "9.0"
+      "os": "11.4"
     }
   ]
 }