Fix identify_magic() with mach-o stub dylibs.

The wrong value was returned and the unittest did not cover the stub dylib case.




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217933 91177308-0d34-0410-b5e6-96231b3b80d8
| -> ||
No functional change.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217934 91177308-0d34-0410-b5e6-96231b3b80d8