Reduce the number of arguments to fail/fail_bounds_check/begin_unwind

[pcwalton]

These appear all the time and result in large code bloat. At least the file and line should be combined into a FailDescriptor static.

[pcwalton]

Also, fail!() and fail!("static string") result in inefficient codegen and code bloat because they call into the string formatter when they don't need to.

[dotdash]

This seems to be done for std. The macro in core still uses the string formatter for all invocations, but I don't even know how to use those.