Add AfterTestHook for extensions

[rpkamp]

Fixes #3391

So extensions have hook for some common functionality that should
happen after every test, regardless of the result.

[codecov]

Codecov Report

Merging #3392 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@             Coverage Diff              @@
##             master    #3392      +/-   ##
============================================
+ Coverage     82.98%   82.98%   +<.01%     
- Complexity     3565     3567       +2     
============================================
  Files           143      143              
  Lines          9496     9498       +2     
============================================
+ Hits           7880     7882       +2     
  Misses         1616     1616

Impacted Files	Coverage Δ	Complexity Δ
src/Runner/Hook/TestListenerAdapter.php	100% <100%> (ø)	30 <0> (+2)	⬆️

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[sebastianbergmann]

Thanks!

[localheinz]

@rpkamp @sebastianbergmann

Unless I am mistaken, I believe the AfterTestHook should have extended the TestHook interface.

Otherwise, if you implement an extension that only implements the AfterTestHook interface, the extension will never run:

https://github.com/sebastianbergmann/phpunit/blob/7.5.0/src/TextUI/TestRunner.php#L227-L239

Since support for phpunit/phpunit:^7.5.0 has ended, a good work-around for this problem could be to implement the another interface that extends the TestHook marker interface in an extension that still needs to support phpunit/phpunit:^7.5.0, even if that particular hook will not be needed.

Ha, looks like this has been fixed in #3762 for phpunit/phpunit:^8.3.0.