customized BlockerExtension does not block correctly for standalone server case

The find-non-progressing-operation operation of /core-service=management/service=management-operations doesn't return the operation id of a blocking operation on standalone. It works on domain mode.
To simulate the blocking operation, install the BlockingExtension from testsuite and call

/subsystem=blocker-test:block(block-point=MODEL,block-time=50000}

Open another jboss-cli.sh and call

/core-service=management/service=management-operations:find-non-progressing-operation

Update:
The example above reveals when people manually install BlockingExtension and run in standalone mode, BlockingExtension does not correctly block and count time, as it does not acquire the exclusive lock.
In domain mode, it acquires the lock by calling context.readResourceForUpdate. This does not affect current test scenarios as the block function is tested in OperationCancellationTestCase under domain mode.