CQ: Add linux_gcc_rel to default trybot set.

BUG=webrtc:7853
NOTRY=True
TBR=ehmaldonado@webrtc.org

Change-Id: I055ff10bd31a107d8ca514b3d681f83876814c8a
Reviewed-on: https://chromium-review.googlesource.com/547756
Reviewed-by: Henrik Kjellander <kjellander@webrtc.org>
Commit-Queue: Henrik Kjellander <kjellander@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#18753}
diff --git a/infra/config/cq.cfg b/infra/config/cq.cfg
index b15b5c9..b43f586 100644
--- a/infra/config/cq.cfg
+++ b/infra/config/cq.cfg
@@ -65,6 +65,7 @@
       builders { name: "linux_tsan2" }
       builders { name: "linux_ubsan" }
       builders { name: "linux_ubsan_vptr" }
+      builders { name: "linux_gcc_rel" }
       builders { name: "linux_more_configs" }
       builders { name: "mac_asan" }
       builders { name: "mac_baremetal" }