Don't artifically restrict input object size.

sys::IdentifyFileType is already conscious of the length, and
object_error::invalid_file_type is returned below anyway if
sys::IdentifyFileType doesn't recognize the file.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@183605 91177308-0d34-0410-b5e6-96231b3b80d8
  Fix a potential bug in r183584.

  r183584 tries to derive some info from the code *AFTER* a call and apply
these derived info to the code *BEFORE* the call, which is not always safe
as the call in question may never return, and in this case, the derived
info is invalid.
  
  Thank Duncan for pointing out this potential bug.

rdar://14073661 


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@183606 91177308-0d34-0410-b5e6-96231b3b80d8