Re-enable linux_ubsan

TBR=phoglund@webrtc.org

Bug: chromium:774973
No-Try: true
Change-Id: I4b89413c9ad266a73f84567765d6c9c87bc65147
Reviewed-on: https://webrtc-review.googlesource.com/22240
Commit-Queue: Edward Lemur <ehmaldonado@webrtc.org>
Reviewed-by: Oleh Prypin <oprypin@webrtc.org>
Reviewed-by: Edward Lemur <ehmaldonado@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20685}

infra/config/cq.cfg

diff --git a/infra/config/cq.cfg b/infra/config/cq.cfg
index ee07382..3b66557 100644
--- a/infra/config/cq.cfg
+++ b/infra/config/cq.cfg
@@ -53,8 +53,7 @@
       builders { name: "linux_msan" }
       builders { name: "linux_rel" }
       builders { name: "linux_tsan2" }
-      # TODO(oprypin): Re-enable when https://crbug.com/774973 is fixed.
-      #builders { name: "linux_ubsan" }
+      builders { name: "linux_ubsan" }
       builders { name: "linux_ubsan_vptr" }
       builders { name: "linux_gcc_rel" }
       builders { name: "linux_more_configs" }