add options to ignore failing tests in prerelease

[mathias-luedtke]

closes #362

@wxmerkt: With this fix you can set ABORT_ON_TEST_FAILURE_UNDERLAY=0 to make your test pass

[130s]

Can we document these 2 variables new to ICI?

Other than that this LGTM. A clarification: What happens when a test fails while neither of ABORT_ON_TEST_FAILURE_{Over, UNDER}LAY are passed (i.e. default behavior)? If this changes the default, that might be noted in the document?

[mathias-luedtke]

This should het merged into the new version.

Can we document these 2 variables new to ICI?

I will add some line to the documentation of the prerelease tests.
They have been defined like this in ros_buildfarm.

What happens when a test fails while neither of ABORT_ON_TEST_FAILURE_{Over, UNDER}LAY are passed (i.e. default behavior)? If this changes the default, that might be noted in the document?

TL;DR: This patch does not change the default of industrial_ci.

In ros_buildfarm these variables default to 0, so failing tests are treated as errors.
In industrial_ci their default is 1. This PR adds an opt-out for this choice.

[130s]

Is there any update?

I might be willing to add documentation. As a "new user" to the recently added changes, I might be able to capture missing info well enough. If that's ok in general, I'm fine in moving forward in merging w/o including more documentation (in that case create follow-up ticket and assign me/anyone appropriate).

[mathias-luedtke]

Is there any update?

This needs to be rebased, but it is prioritized

Some notes on these flags could be added here:
https://github.com/ros-industrial/industrial_ci/blob/master/doc/index.rst#run-ros-prerelease-test
Just to comment on the non-default behavior, which is (examle)

By default this script will continue even if tests fail.
If you want the script to abort and return a non-zero return code
you can set the environment variable ABORT_ON_TEST_FAILURE=1.
You can also set ABORT_ON_TEST_FAILURE_UNDERLAY=1 or
ABORT_ON_TEST_FAILURE_OVERLAY=1 to only affect a specific workspace.