When master node is set to zero exectuors,
a matrix job triggers a pipeline job (with blocking) doesn't work.

From Matrix job console, it would show:
Waiting for the completion of "<PIPELINE_JOB_NAME>".

But the pipeline job doesn't start and it doesn't have queue jobs either.
It's just like the trigger was not sent,
but the matrix job is waiting for return indefinitely.

Only from Jenkins master jenkins.log, you can see:

Oct 02, 2018 1:27:29 PM hudson.model.Executor resetWorkUnit

WARNING: Executor #-1 for master grabbed hudson.model.queue.WorkUnit@2cbaff74[work=PIPELINE_JOB] from queue but master went off-line before the task's worker thread started. No termination trace available.

Jenkins either should queued the job to wait for master executors to be available,
or should returns trigger error back to the matrix job
instead of letting the job wait for the return indefinitely.