fix #6814: ignore php 5.5 scalar class name resolution
#6814 #6946 - checking against `PHP_VERSION_ID` as `version_compare()` is unreliable
#6814 #6946 - adding missing `@group` annotations to newly introduced test cases
Merge branch 'hotfix/#6946-ignore-php-5-5-scalar-class-name-resolution'

Close #6946
Close #6814