Enable deadline tests for FastRTPS (#438)

* improve robustness of test_events

Signed-off-by: Miaofei <miaofei@amazon.com>

* refactor code

Signed-off-by: Miaofei <miaofei@amazon.com>

* enable testing of fastrtps

Signed-off-by: Miaofei <miaofei@amazon.com>

* fix failing tests and remove useless tests

Signed-off-by: Miaofei <miaofei@amazon.com>

* disable liveliness tests for fastrtps as it is not supported

Signed-off-by: Miaofei <miaofei@amazon.com>