merge MMcM: Update tests to not look for .t3expected files. Rename existing ones.

Merge pull request #1111 from MMcM/sql-layer/rename-t3expected
https://github.com/FoundationDB/sql-layer/pull/1111
There is no meaningful distinction between types and expressions at the serice level; collapse those packages.
Add a types registry to the types registry service (!)
Now that types registry is a service, it needs to be wired all over the place, particularly in unit tests.