Replace ios-simulator-swarming bot with ios-simulator-xcode-clang

ios/build/bots/chromium.mac/ios-simulator-xcode-clang.json

 {
   "owners": [
-    "dpranke",
+    "sdefresne",
     "smut"
   ],
   "comments": [
     "Tests for 64-bit iOS 10.0 simulators.",
     "Tests run on iPhone 6s and iPad Air 2, both 64-bit.",
     "Build is performed with gn+ninja."
   ],
   "xcode version": "8.0",
   "GYP_DEFINES": [
     "OS=ios",
     "chromium_ios_signing=0",
     "component=static_library",
     "use_goma=1",
     "gomadir=$(goma_dir)",
     "target_subarch=both"
   ],
   "gn_args": [
     "is_debug=true",
     "target_os=\"ios\"",
     "ios_enable_code_signing=false",
     "is_component_build=false",
     "use_goma=true",
     "goma_dir=\"$(goma_dir)\"",
     "target_cpu=\"x64\"",
-    "additional_target_cpus=[\"x86\"]"
+    "additional_target_cpus=[\"x86\"]",
+    "use_xcode_clang=true"
   ],
   "mb_type": "gn",
   "compiler": "ninja",
-  "additional_compile_targets": ["gn_all"],
   "configuration": "Debug",
   "sdk": "iphonesimulator10.0",
   "tests": [
     {
       "include": "common_tests.json",
       "device type": "iPhone 6s",
       "os": "10.0"
     },
     {
       "include": "common_tests.json",
       "device type": "iPad Air 2",
       "os": "10.0"
     }
   ]
 }