Most tests were using %swift or similar substitutions, which did not
include the target triple and SDK. The driver was defaulting to the
host OS. Thus, we could not run the tests when the standard library was
not built for OS X.
Swift SVN r24504
Instead of hardcoding Builtin.Word to be an alias for Builtin.Int64, make it its own type of abstract pointer width.
- Change BuiltinIntegerType's width representation to accommodate abstract widths.
- In the AST and in SIL, store values of the types as the greatest supported size for the abstract width (64 bits for a pointer).
- Add some type safety to the ([sz]ext|trunc)(OrBitCast)? builtins that they're used appropriately given the upper and lower bounds of the abstract sizes they're working with.
- Now that Builtin.Word is a distinct type, give it its own mangling.
- In IRGen, lower pointer-sized BuiltinIntegerType appropriately for the target, and truncate lowered SIL values if necessary.
Fixes <rdar://problem/15367913>.
Swift SVN r10467
