This is only a test-fix.
apply_ops_DDL_operation_does_not_take_global_X.js makes sure the oplog application of all DDL operations will not take a Global X lock. It verifies that by hanging a read which takes a Global IS lock and then applying a bunch of DDL operations.
However, applying DDL operations will also take a PBWM lock in X mode. The read will not take PBWM lock when snapshot read functionality is enabled. Otherwise, the read will take PBWM lock in IS mode, which blocks the DDL operations.
Therefore, the test only works with storage engine with snapshot read support.