This one shows the unfortunate consequence that we need
Lazy[Forward|Bidirectional|RandomAccess]Collection. There's gonna be a
whole lotta gyb'bing going on...
Swift SVN r19316
There's a lot more work to do here, but start to categorize tests
along the lines of what a specification might look like, with
directories (chapters) for basic concepts, declarations, expressions,
statements, etc.
Swift SVN r9958