Fixed counting exception

Fixed "Invalid parameter number: number of bound variables does not match number of tokens " exception during execution count on Query where select part of query contains :parameters.
Allowed to get count query from paginator.
Test parameter removing parameters passed to select part of query.
Testing SQLs in functional test is not necessary
Filtering by auto-increnement field causes test error.

Executing the same test many times causes error because AI fields.
Missing doc block, removed parse() parameter.

Missing doc block, removed parse() parameter.
#1188 - removing unused variable assignments
#1188 - making `Doctrine\ORM\Tools\Pagination\Paginator#getCountQuery()` private, as it is an implementation detail
#1188 - accessing `Doctrine\ORM\Tools\Pagination\Paginator#getCountQuery()` via reflection for test purposes
#1188 - minor CS fixes (avoiding DQL one-liner)
#1188 - `assertCount` instead of `assertEquals`
#1188 - Importing parser class
#1188 - Simplified and optimized parameter un-setting logic
Merge branch 'hotfix/#1188-support-count-queries-with-parameters-in-removed-query-parts-2.4-backport' into 2.4

Merge #1188 into 2.4