[co19] Roll co19 to 53dd55a31d345320a6aa2b6eea0467f868b72377

2020-09-29 irina.arkhipets@gmail.com Fixes 942: Simple-bounds tests corrected.
2020-09-28 irina.arkhipets@gmail.com Additional fix for 916: LibTest\Spread-collections tests adopted for null safety.

Change-Id: I150f72e0d90815d3802ddae6b33de2eb24d88dd1
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/165161
Reviewed-by: William Hesse <whesse@google.com>
diff --git a/DEPS b/DEPS
index 87d2db4..fbc3992 100644
--- a/DEPS
+++ b/DEPS
@@ -44,7 +44,7 @@
   # co19 is a cipd package. Use update.sh in tests/co19[_2] to update these
   # hashes. It requires access to the dart-build-access group, which EngProd
   # has.
-  "co19_rev": "58e95961ea492a749ca6eccf5586fdf8271f8266",
+  "co19_rev": "53dd55a31d345320a6aa2b6eea0467f868b72377",
   "co19_2_rev": "e48b3090826cf40b8037648f19d211e8eab1b4b6",
 
   # The internal benchmarks to use. See go/dart-benchmarks-internal