Produce another specific error message for a malformed Mach-O file when a load

command other than the first one is past the end of the load commands.

This is like the test case in test/Object/macho-invalid.test for
macho64-invalid-incomplete-load-command but it is the second load command
that is past the end of all the load commands instead of the first.

The code in the constructor for MachOObjectFile that loops over the load
commands used getNextLoadCommandInfo() which was not producing
a good error message.  So that was fixed and a test case was added.

llvm-svn: 268403