Change the file size field of StatusInfo to be uint64_t instead of size_t
so that we know it is always 64 bits. This prevents some overflow on
systems where size_t is 32 bits when it ought to be 64.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@28726 91177308-0d34-0410-b5e6-96231b3b80d8