closed #4639: FileUtils::isFileExist doesn't consider SearchPaths and ResolutionOrders
issue #4639: Reverts the definition of FileUtils::isFileExist, remove
the second parameter(outFullPath).
Merge pull request #6110 from dumganhar/iss4639-isfileexist

closed #4639: FileUtils::isFileExist doesn't consider SearchPaths and ResolutionOrders