[#4618] Fix fromReflectedFileName()

- method was not properly detecting when a file does not exist, in part
  due to using no longer implemented methods of FileReflection.
[#4618] Typo in variable name
[#4618] File check in include_path can't be do as part of the fix because $includeIfNotAlreadyIncluded lost his functionality
[#4618] Fix test assets
[#4618] PHP files needs at least two lines
Merge branch 'hotfix/4618'

Close #4618