Add a way for schema operations to fail immediately if resources aren't available

It would be good if there were some way to fail operations immediately if a lock/handle/resource is not available.

For example if there is a checkpoint in progress, and an application wants to try dropping a table. It'd be nice if the drop could return EBUSY immediately, rather than waiting for the checkpoint.

This functionality would be optional and could be exposed a couple of ways:

• Add a new setting to the session handle (reconfigurable) that turns the no-wait on for all schema operations on a session handle.
• Add a new setting to all APIs that do schema level operations (yuck).