merge(3p/absl): subtree merge of Abseil up to e19260f

... notably, this includes Abseil's own StatusOr type, which
conflicted with our implementation (that was taken from TensorFlow).

Change-Id: Ie7d6764b64055caaeb8dc7b6b9d066291e6b538f

third_party/abseil_cpp/ci/cmake_install_test.sh

@@ -20,11 +20,13 @@ if [[ -z ${ABSEIL_ROOT:-} ]]; then
   ABSEIL_ROOT="$(realpath $(dirname ${0})/..)"
 fi
 
+source "${ABSEIL_ROOT}/ci/cmake_common.sh"
+
 source "${ABSEIL_ROOT}/ci/linux_docker_containers.sh"
 readonly DOCKER_CONTAINER=${LINUX_GCC_LATEST_CONTAINER}
 
 time docker run \
-    --volume="${ABSEIL_ROOT}:/abseil-cpp:ro" \
+    --mount type=bind,source="${ABSEIL_ROOT}",target=/abseil-cpp,readonly \
     --workdir=/abseil-cpp \
     --tmpfs=/buildfs:exec \
     --cap-add=SYS_PTRACE \