This commit is the final step in ensuring all the pipes commit what they
should. It also asserts this actually happens, enabling us to easily
catch future problems.
Replace the stub implementation of invalidation with the proper
implementation. A ReadPathCache is added to each global so that it can
keep tracks of what target are associated to which read paths.
This commit changes the following method names across the codebase:
* `storeToDisk` -> `store`
* `loadFromDisk` -> `load`
This has been done since the storage is no longer bound to the local
storage.
`ReadOnlyContainers` is defined to be a `llvm::StringMap`
of a further `llvm::StringMap` of `std::unique_ptr`s of
`ContainerBase`. A logic issue has been addressed by
properly dereferincing the inner map.
Ivan Krysak