[zendframework/zf2#4919] Cleanup for consistency
[zendframework/zf2#4919] Cleanup for consistency

- Updated docblocks to remove `@static` annotation and to align
  properties (to be consistent with rest of class).
- Return early when cached values are present, thus promoting the meat
  of the method to the method body.

akrabat/zend-stdlib,adamlundrigan/zend-stdlib,sravanchandj/zend-stdlib,weierophinney/zend-stdlib,php-refactoring/zend-array-utility,ezimuel/zend-stdlib,MadCat34/zend-stdlib