Googletest export

Use newer Docker images in CI

The new floor image contains GCC 5.5.0, like the old one.

PiperOrigin-RevId: 402402465

ci/linux-presubmit.sh

@@ -31,8 +31,8 @@
 
 set -euox pipefail
 
-readonly LINUX_LATEST_CONTAINER="gcr.io/google.com/absl-177019/linux_hybrid-latest:20210525"
-readonly LINUX_GCC_FLOOR_CONTAINER="gcr.io/google.com/absl-177019/linux_gcc-floor:20201015"
+readonly LINUX_LATEST_CONTAINER="gcr.io/google.com/absl-177019/linux_hybrid-latest:20210617"
+readonly LINUX_GCC_FLOOR_CONTAINER="gcr.io/google.com/absl-177019/linux_gcc-floor:20210617"
 
 if [[ -z ${GTEST_ROOT:-} ]]; then
   GTEST_ROOT="$(realpath $(dirname ${0})/..)"