rclcpp_action.test_client is flaky  #744

Bug report

Required Info:

• Operating System:
  • Ubuntu 18.04
• Installation type:
  • source
• Version or commit hash:
  • 8553fbe
• DDS implementation:
  • Fast-RTPS
• Client library (if applicable):
  • rclcpp

Steps to reproduce issue

With the latest source checked out:

colcon build --packages-up-to rclcpp_action
colcon test --packages-select rclcpp_action --retest-until-fail 10

Expected behavior

Build and tests without error.

Actual behavior

No test results for rclcpp_action.test_client:

build/rclcpp_action/test_results/rclcpp_action/test_client.gtest.xml: 1 test, 0 errors, 1 failure, 0 skipped
- rclcpp_action test_client.gtest.missing_result
  <<< failure message
    The test did not generate a result file.
  >>>

Additional information

This is also happening on aarch64 builds, which I noticed here: https://ci.ros2.org/job/ci_linux-aarch64/3428/testReport/.