Make @Stepwise work for iterated features

[kriegaex]

@Stepwise can now be applied to feature methods. The effects are:

1. the feature is switched to ExecutionMode.SAME_THREAD, similarly to how whole specs are switched to the same execution mode when using the annotation on class level.

2. After the first error or failure occurs in any iteration, all subsequent iterations are going to be skipped.

Fixes #1008.

To do:

• Test automation
• Spock manual update
• Release notes update

Special thanks to @leonard84 who helped me evolve my separate extension with more complex code structure (because I started implementing it for Spock 1.3 where that was necessary) into something more elegant and minimal. Without him, it would not look quite as beautiful. In the end, I merely had to migrate it from a separate annotation + extension into the existing StepwiseExtension, where it is only a small change.

[codecov]

Codecov Report

Merging #1442 (4bac821) into master (224a2a0) will increase coverage by 0.05%.
The diff coverage is 100.00%.

@@             Coverage Diff              @@
##             master    #1442      +/-   ##
============================================
+ Coverage     79.53%   79.59%   +0.05%     
- Complexity     4007     4010       +3     
============================================
  Files           404      404              
  Lines         12550    12563      +13     
  Branches       1640     1640              
============================================
+ Hits           9982     9999      +17     
+ Misses         1973     1969       -4     
  Partials        595      595              

Impacted Files	Coverage Δ
...k/runtime/extension/builtin/StepwiseExtension.java	94.59% <100.00%> (+2.92%)	⬆️
...ork/runtime/ParameterizedFeatureChildExecutor.java	100.00% <0.00%> (+15.38%)	⬆️

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[kriegaex]

@leonard84, from my perspective, this is done and ready to be merged, unless you find issues in my most recent commits. But better safe than sorry, so take due time to review them. I do not know your usual merge practice, so if you want me to rebase on the main branch and/or squash the commits into fewer ones, just let me know. I am not going to rebase or squash anything now, because it might confuse you, reviewing incrementally.

[leonard84]

I do not know your usual merge practice, so if you want me to rebase on the main branch and/or squash the commits into fewer ones, just let me know. I am not going to rebase or squash anything now, because it might confuse you, reviewing incrementally.

Just commit normally, I normally squash with Github when merging back to master.

[leonard84]

Thanks for the PR @kriegaex