This doesn't actually break the circular type-checking issues with
have with associated type inference, but it makes them less
painful. Fixes rdar://problem/20549165.
While here, and as a test, remove the _prext_underestimateCount
workound from the library. _CollectionDefaultsType now refines
_SequenceDefaultsType.
Swift SVN r27368
The standard library has grown significantly, and we need a new
directory structure that clearly reflects the role of the APIs, and
allows future growth.
See stdlib/{public,internal,private}/README.txt for more information.
Swift SVN r25876