[ios] Properly target ios-webview bots to 10.13.

Also adds x86 compilation.

Change-Id: I10adee5c61795ea0f13004db26471367e0482c7a
Reviewed-on: https://chromium-review.googlesource.com/c/1296877Reviewed-by: Marc Treib <treib@chromium.org>
Reviewed-by: John Budorick <jbudorick@chromium.org>
Commit-Queue: Justin Cohen <justincohen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#602396}

ios/build/bots/chromium.mac/ios-webview.json

@@ -11,6 +11,7 @@
     "is_debug=true",
     "symbol_level=1",
     "target_cpu=\"x64\"",
+    "additional_target_cpus=[\"x86\"]",
     "target_os=\"ios\"",
     "use_goma=true"
   ],
@@ -19,46 +20,91 @@
     {
       "app": "ios_web_view_unittests",
       "device type": "iPhone 5s",
+      "dimensions": [
+        { "os": "Mac-10.13.4", "pool": "Chrome" },
+        { "os": "Mac-10.13.5", "pool": "Chrome" },
+        { "os": "Mac-10.13.6", "pool": "Chrome" }
+      ],
       "os": "10.3"
     },
     {
       "app": "ios_web_view_inttests",
       "device type": "iPhone 5s",
+      "dimensions": [
+        { "os": "Mac-10.13.4", "pool": "Chrome" },
+        { "os": "Mac-10.13.5", "pool": "Chrome" },
+        { "os": "Mac-10.13.6", "pool": "Chrome" }
+      ],
       "os": "10.3"
     },
     {
       "app": "ios_components_unittests",
       "device type": "iPhone 5s",
+      "dimensions": [
+        { "os": "Mac-10.13.4", "pool": "Chrome" },
+        { "os": "Mac-10.13.5", "pool": "Chrome" },
+        { "os": "Mac-10.13.6", "pool": "Chrome" }
+      ],
       "os": "10.3"
     },
     {
       "app": "components_unittests",
       "device type": "iPhone 5s",
+      "dimensions": [
+        { "os": "Mac-10.13.4", "pool": "Chrome" },
+        { "os": "Mac-10.13.5", "pool": "Chrome" },
+        { "os": "Mac-10.13.6", "pool": "Chrome" }
+      ],
       "os": "10.3"
     },
     {
       "app": "net_unittests",
       "device type": "iPhone 5s",
+      "dimensions": [
+        { "os": "Mac-10.13.4", "pool": "Chrome" },
+        { "os": "Mac-10.13.5", "pool": "Chrome" },
+        { "os": "Mac-10.13.6", "pool": "Chrome" }
+      ],
       "os": "10.3"
     },
     {
       "app": "ios_net_unittests",
       "device type": "iPhone 5s",
+      "dimensions": [
+        { "os": "Mac-10.13.4", "pool": "Chrome" },
+        { "os": "Mac-10.13.5", "pool": "Chrome" },
+        { "os": "Mac-10.13.6", "pool": "Chrome" }
+      ],
       "os": "10.3"
     },
     {
       "app": "ios_web_unittests",
       "device type": "iPhone 5s",
+      "dimensions": [
+        { "os": "Mac-10.13.4", "pool": "Chrome" },
+        { "os": "Mac-10.13.5", "pool": "Chrome" },
+        { "os": "Mac-10.13.6", "pool": "Chrome" }
+      ],
       "os": "10.3"
     },
     {
       "app": "ios_web_inttests",
       "device type": "iPhone 5s",
+      "dimensions": [
+        { "os": "Mac-10.13.4", "pool": "Chrome" },
+        { "os": "Mac-10.13.5", "pool": "Chrome" },
+        { "os": "Mac-10.13.6", "pool": "Chrome" }
+      ],
       "os": "10.3"
     },
     {
       "app": "ios_web_shell_egtests",
       "device type": "iPhone 5s",
+      "dimensions": [
+        { "os": "Mac-10.13.4", "pool": "Chrome" },
+        { "os": "Mac-10.13.5", "pool": "Chrome" },
+        { "os": "Mac-10.13.6", "pool": "Chrome" }
+      ],
       "os": "10.3",
       "xctest": true
     }