Increase timeout for desugared library head builder

Change-Id: I921b8ffbfbd07343df6f77b6eaadbf97a7b6aac3

infra/config/global/cr-buildbucket.cfg

diff --git a/infra/config/global/cr-buildbucket.cfg b/infra/config/global/cr-buildbucket.cfg
index 85170a7..c5485c1 100644
--- a/infra/config/global/cr-buildbucket.cfg
+++ b/infra/config/global/cr-buildbucket.cfg
@@ -141,6 +141,7 @@
     }
     builders {
       name: "desugared_library_head"
+      execution_timeout_secs: 43200  # 12h
       mixins: "linux"
       mixins: "normal"
       priority: 26