Give each embedded Pulsar MQ test instance its own AMQP queues

The module-level tool test instance in test_pulsar_embedded_mq.py stays
up until pytest leaves the module, so it is still consuming from the
broker while the purge test classes in the same file run. All of them
used the default pulsar_ queue names, and the older instance's embedded
Pulsar could take the new instance's setup message and stage the job in
its own directory; the job then failed with tool_script.sh missing.

test/integration/test_pulsar_embedded_mq.py

@@ -3,6 +3,7 @@
 import os
 import string
 import tempfile
+import uuid
 
 import pytest
 
@@ -27,8 +28,10 @@ runners:
       conda_auto_init: false
       conda_auto_install: false
       message_queue_url: ${amqp_url}
+      amqp_key_prefix: ${amqp_key_prefix}
       staging_directory: ${jobs_directory}
     amqp_url: ${amqp_url}
+    amqp_key_prefix: ${amqp_key_prefix}
 execution:
   default: pulsar_mq_environment
   environments:
@@ -57,7 +60,12 @@ def _handle_galaxy_config_kwds(cls, config):
     safe_makedirs(jobs_directory)
     job_conf_template = string.Template(JOB_CONF_TEMPLATE)
     job_conf_str = job_conf_template.substitute(
-        amqp_url=AMQP_URL, jobs_directory=jobs_directory, galaxy_home=os.path.join(SCRIPT_DIRECTORY, os.pardir)
+        amqp_url=AMQP_URL,
+        # The module's tool test instance outlives the classes that run after it; queues of its
+        # own keep its embedded Pulsar from taking their jobs.
+        amqp_key_prefix=f"pulsar_{uuid.uuid4().hex[:12]}_",
+        jobs_directory=jobs_directory,
+        galaxy_home=os.path.join(SCRIPT_DIRECTORY, os.pardir),
     )
     with tempfile.NamedTemporaryFile(suffix="_mq_job_conf.yml", mode="w", delete=False) as job_conf:
         job_conf.write(job_conf_str)