Re-sort the lldb.xcodeproj project file and commit the script

that I used to sort it to scripts/sort-pbxproj.rb.  It turns
out that Xcode will perturb the order of the file lists 
every time we add a file, following its own logic, and unfortunately
we'll still end up with lots of merge conflicts when that tries
to merge to the github swift repositories.  We talked this over
and we're going to keep it in a canonical state by running this
script over it when Xcode tries to reorder it.

llvm-svn: 336158