Fixed LP bug #668290.

Prohibited to use hash join algorithm BNLH if join attributes
need non-binary collations. It has to be done because BNLH does
not support join for such attributes yet.
Later this limitations will be lifted.

Changed default collations for the schemes of some test cases
to preserve the old execution plans.

sql/sql_select.h

@@ -391,6 +391,7 @@ typedef struct st_join_table {
     return max_used_fieldlength;
   }
   double get_partial_join_cardinality() { return partial_join_cardinality; }
+  bool hash_join_is_possible();
 } JOIN_TAB;