It doesn't make sense to allow selects from I_S but disallow selects
that don't use any tables at all, because any (disallowed) select that
doesn't use tables can be made allowed by adding
"FROM I_S.COLLATIONS LIMIT 1" to the end.

And it break mysql-test rather badly, even check-testcase.test
fails on its first `SELECT '$tmp' = 'No such row'`

This reverts 9a896148, c5dd2abf, and 33028f7c:
Refs: MW-245 - changed logic so that in non primary node it is possible to do SET + SHOW + SELECT from information and pfs schema, when dirty reads are not enabled - however, non table selects are not allowed (e.g. SELECT 1)
Refs MW-245 - logic was wrong in detecting if queries are allowed in non primary node. it allowed select with no table list to execute even if dirty reads was not specified
Refs: MW-245 - Adjust tests to account for the new behavior.