[feat] Deprecate the use of the @parameterized_test decorator

[vkarak]

Fixes #1849.

Implementation details

Since I had to convert everything to the built-in parameter in the unit tests, I introduced the notion of force loading the test, in which case the loader first unloads the test module if it has already been loaded and then reloads it. This change is implemented in a larger extent in #1848, but here I am only using it in one unit test.

[pep8speaks]

Hello @vkarak, Thank you for updating!

Cheers! There are no PEP8 issues in this Pull Request!Do see the ReFrame Coding Style Guide

Comment last updated at 2021-04-19 13:33:29 UTC

[codecov-commenter]

Codecov Report

❗ No coverage uploaded for pull request base (master@91f481f). Click here to learn what that means.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##             master    #1934   +/-   ##
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  Coverage          ?   87.88%           
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  Files             ?       50           
  Lines             ?     8610           
  Branches          ?        0           
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  Hits              ?     7567           
  Misses            ?     1043           
  Partials          ?        0           

Impacted Files	Coverage Δ
reframe/core/decorators.py	83.19% <100.00%> (ø)
reframe/frontend/loader.py	92.50% <100.00%> (ø)
reframe/utility/__init__.py	92.82% <100.00%> (ø)

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[jjotero]

I think we should also add a few fixmes or perhaps even create an issue to do the cleanup after the deprecation is done.
The main thing that I have in mind is the _register_test function, which can be massively simplified to just forward whichever *args and **kwargs from the decorator to the test constructor.
Also, (this one is for 4.0) I think it would also make sense to change the simple_test decorator to just @test.

[vkarak]

@jjotero Yes, all these should be addressed properly by #1833 which is scheduled for 4.x