Adding new macbook airs to the luci configs

Bug: 779634
Change-Id: Iba3bed868177e7caa31714573c10eaae1a0571c1
Reviewed-on: https://chromium-review.googlesource.com/1012200Reviewed-by: Ned Nguyen <nednguyen@google.com>
Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>
Reviewed-by: Emily Hanley <eyaich@chromium.org>
Commit-Queue: Emily Hanley <eyaich@chromium.org>
Cr-Commit-Position: refs/heads/master@{#550991}

infra/config/global/luci-milo-dev.cfg

@@ -1303,9 +1303,9 @@ consoles: {
     short_name: "12"
   }
   builders: {
-    name: "buildbot/chromium.perf/Mac Retina Perf"
+    name: "buildbot/chromium.perf/mac-10_12_laptop_low_end-perf"
     category: "perf|mac"
-    short_name: "ret"
+    short_name: "low"
   }
   builders: {
     name: "buildbot/chromium.perf/Mac Pro 10.11 Perf"

infra/config/global/luci-milo.cfg

@@ -1356,11 +1356,6 @@ consoles: {
     category: "perf|mac"
     short_name: "12"
   }
-  builders: {
-    name: "buildbot/chromium.perf/Mac Retina Perf"
-    category: "perf|mac"
-    short_name: "ret"
-  }
   builders: {
     name: "buildbot/chromium.perf/Mac Pro 10.11 Perf"
     category: "perf|mac"
@@ -1371,6 +1366,11 @@ consoles: {
     category: "perf|mac"
     short_name: "air"
   }
+  builders: {
+    name: "buildbot/chromium.perf/mac-10_12_laptop_low_end-perf"
+    category: "perf|mac"
+    short_name: "low"
+  }
   builders: {
     name: "buildbot/chromium.perf/Linux Perf"
     category: "perf"