Run ios-device, ios-device-xcode-clang, and ios-simulator-xcode-clang…

… at 10%.

ios-device has a very long pending queue at 100%, and I'd still like
to get timing information from the other two.

TBR=dpranke@chromium.org

Bug: 740301
Change-Id: I52caba49f65add51e7b1cae3b9ea175dd4d56e36
Reviewed-on: https://chromium-review.googlesource.com/587422
Commit-Queue: John Budorick <jbudorick@chromium.org>
Reviewed-by: smut <smut@google.com>
Cr-Commit-Position: refs/heads/master@{#489810}

infra/config/cq.cfg

@@ -70,12 +70,19 @@ verifiers {
       # https://crbug.com/739556; make this non-experimental ASAP.
       builders {
         name: "ios-device"
-        experiment_percentage: 100
+        experiment_percentage: 10
       }
       # https://crbug.com/739556
-      # builders { name: "ios-device-xcode-clang" }
+      builders {
+        name: "ios-device-xcode-clang"
+        experiment_percentage: 10
+      }
       builders { name: "ios-simulator" }
-      # builders { name: "ios-simulator-xcode-clang" }
+      # https://crbug.com/739556
+      builders {
+        name: "ios-simulator-xcode-clang"
+        experiment_percentage: 10
+      }
       builders { name: "mac_chromium_compile_dbg_ng" }
       builders { name: "mac_chromium_rel_ng" }
     }