Get an abstract defined service from an alias

When you want to get a service leading to to an abstract factory from an alias.
added test  for Zend\ServiceManager\ServiceManager::get  : testGetAbstractFactoryWithAlias
Merge pull request #5752 from jmleroux/patch-2

Get an abstract defined service from an alias
[#5752] CS fixes

- multiline comment formatting, trailing whitespace
Merge branch 'hotfix/5752'

Close #5752
Fixes #5535