swift234

Introduce Builtin.staticReport, which allows compiler diagnostic reporting.

- Introduces the Builtin
- If the first parameter evaluates to '1', the dataflow diagnostics pass produces a diagnostic.
- The Builtin gets cleaned up before IRGen, but not before SIL serialization.

This patch also removes the current, overflow warning and XFAILs one of the tests. The other test is switched to use Builtin.staticReport.

TODO:
 - Utilize the other parameters to the builtin - the Message and IsError flag.
 - Use this Builtin within the stdlib.

Swift SVN r8939