Add failing test case for view_renderer leaking to rails (#144)

[robink]

Added some test cases (and a failing one) according to https://github.com/komposable/komponent/issues/144

[coveralls]

Pull Request Test Coverage Report for Build 933

• 3 of 3 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.006%) to 99.454%

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Totals
Change from base Build 814:	0.006%
Covered Lines:	182
Relevant Lines:	183

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💛 - Coveralls

[Spone]

Thanks @robink! We still have this issue on ruby-head which is unrelated to your changes, we'll have a look soon!

[Spone]

Thanks @robink for your work on this!