[ReconstructType] Run clang-format on this file

I wouldn't normally do a bulk reformat like this, but in this case I
think the benefits of consistently formatting the file outweigh the
costs, because (a) there is no substantive history to this file yet in
the swift repo, and (b) there are widespread and *distracting* style
differences like brace-placement and spaces before opening (.

Author: benlangmuir