Adds the next bit of support for llvm-objdump’s -private-headers for executable Mach...

Adds the next bit of support for llvm-objdump’s -private-headers for executable Mach-O files.

This adds the printing of more load commands, so that the normal load commands
in a typical X86 Mach-O executable can all be printed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217172 91177308-0d34-0410-b5e6-96231b3b80d8