sync svn r24702 - support application/x-zip in Zend_Validate_File_IsCompressed
Merge pull request #4431 from sasezaki/validator_x_zip

sync svn r24702 - support application/x-zip in Validator\File\IsCompressed
[#4431] Refactored tests slightly

- Was observing test failures due to calling markTestSkipped() inside a
  data provider.
- Created new skipIfBuggyMimeContentType() method to call to skip a test
  if mime_content_type() returns buggy information for zip files
[#4431] Better mime_content_type behavior

- Only skip if we're dealing with a zip type in the first place.
[#4431] Remove usage of mime_content_type

- Deprecated since 5.3.0, and fileinfo is enabled by default in vanilla PHP
  builds. It makes no sense to fallback to it, when finfo does a much better
  job.
Merge branch 'hotfix/4431'

Close #4431