This patch adds the notion of "Facade" locations which can be reported
from a ScriptedResolver instead of the actual underlying breakpoint
location for the breakpoint. Also add a "was_hit" method to the scripted
resolver that allows the breakpoint to say which of these "Facade"
locations was hit, and "get_location_description" to provide a
description for the facade locations.
I apologize in advance for the size of the patch. Almost all of what's
here was necessary to (a) make the feature testable and (b) not break
any of the current behavior.
The motivation for this feature is given in the "Providing Facade
Locations" section that I added to the python-reference.rst so I won't
repeat it here.
rdar://152112327