The tests were matching the previous implementation's output, which sometimes produced 'unknown' and sometimes 'unrelated' in cases where there was no expected type from the context.
This adjusts the tests for the difference between line endings on
different platforms. Windows uses CRLF while most Unicies use LF. This
was exposed during the update to the new LLVM snapshot.
- Use `performParseAndResolveImportsOnly()` to invoke the frontend
- Do `bindExtensions()` in `ide::typeCheckContextUntil()`
- Typecheck preceding `TopLevelCodeDecl`s only if the compleiton is in
a `TopLevelCodeDecl`
- Other related tweaks
rdar://problem/56636747
The code goes into its own sub-tree under 'tools' but tests go under 'test',
so that running 'check-swift' will also run all the SourceKit tests.
SourceKit is disabled on non-darwin platforms.
