Rewrite the testsuite for the JCRHttpCache

[joerghoh]

• use SlingContext instead lots of mocks.
• and fix some issues on the way

[update-changelog]

Thanks for opening this pull request! The maintainers of this repository would appreciate it if you would update the CHANGELOG.md file with this pull request.

[coveralls]

Pull Request Test Coverage Report for Build 5211

• 28 of 28 (100.0%) changed or added relevant lines in 4 files are covered.
• 31 unchanged lines in 4 files lost coverage.
• Overall coverage increased (+0.4%) to 55.62%

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Files with Coverage Reduction	New Missed Lines	%
bundle/src/main/java/com/adobe/acs/commons/httpcache/store/jcr/impl/handler/EntryNodeToCacheContentHandler.java	1	86.0%
bundle/src/main/java/com/adobe/acs/commons/httpcache/store/jcr/impl/handler/EntryNodeToCacheKeyHandler.java	1	90.91%
bundle/src/main/java/com/adobe/acs/commons/httpcache/store/jcr/impl/visitor/TotalCacheSizeVisitor.java	14	0.0%
bundle/src/main/java/com/adobe/acs/commons/httpcache/store/jcr/impl/visitor/InvalidateByCacheConfigVisitor.java	15	0.0%

Totals
Change from base Build 5197:	0.4%
Covered Lines:	14979
Relevant Lines:	26931

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💛 - Coveralls

[joerghoh]

@niekraaijmakers WDYT?

[niekraaijmakers]

I approve :)

[davidjgonzalez]

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