Stacked coursemodinfo cache broken due to requirelockingbeforewrite

Steps to reproduce:

• On latest master
• Visit /cache/admin.php and add a new FIle Cache instance.
• Set the store name to "Local" and set the path to somewhere writable (e.g. /tmp/filecache). Tick "Auto create directory" and click "Save changes").
• Under "Known cache definitions" find "Accumulated information about modules and sections for each course" (coursemodinfo) and click "Edit mappings"
• Set "Primary store" to "Local", "Final store" to "default_application", and click "Save changes"
• You will see the error "Attempted to set cache key "1" without a lock. Locking before writes is required for core/coursemodinfo"

This is due to the changes made in MDL-67020 not taking locking across multiple cache layers into account. A lock is not being created before attempting to set a key on a parent cache, or when reading a value from a parent cache and storing it in the child cache.