[Android CQ]: Enable binary size trybot.

The android-binary-size bot blocks CLs that do one of the following:
  * Increase normalized_apk_size > 16 kb
  * Add more than 50 Java methods
  * Add/increase the size of an uncompressed pak > 1 kb

The trybot emits useful debugging information as bot steps and
includes a link to an interactive Supersize HTML report.

These checks are skipped for autorollers and for CLs with
"Binary-Size:" in the commit message.

Bug: 702625
Change-Id: I3e9dee26e96fd0d1cfe5f86ec1b8c717fa1abf2f
Reviewed-on: https://chromium-review.googlesource.com/1254502Reviewed-by: agrieve <agrieve@chromium.org>
Reviewed-by: John Budorick <jbudorick@chromium.org>
Commit-Queue: Eric Stevenson <estevenson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#595460}

infra/config/branch/cq.cfg

@@ -31,11 +31,7 @@ verifiers {
     buckets {
       name: "luci.chromium.try"
       builders { name: "android_arm64_dbg_recipe" }
-      # https://crbug.com/702625
-      builders {
-        name: "android-binary-size"
-        experiment_percentage: 100
-      }
+      builders { name: "android-binary-size" }
       builders { name: "android_clang_dbg_recipe" }
       builders { name: "android_compile_dbg" }
       builders { name: "android_cronet" }