Investigate/replace use of thread local in ActiveBulkThread

[ormsbee]

The following is not async-safe:

openedx-platform/xmodule/modulestore/__init__.py

Lines 168 to 174 in 0a9cb22

	class ActiveBulkThread(threading.local):
	"""
	Add the expected vars to the thread.
	"""
	def __init__(self, bulk_ops_record_type, **kwargs):
	super().__init__(**kwargs)
	self.records = defaultdict(bulk_ops_record_type)