[llvm] r197052 - [arm] Implement ARM .arch directive.

[Tim Northover]

> 0. Program arguments: llvm-mc -arch=arm -filetype=obj
> <stdin>: The file was not recognized as a valid object file
> FileCheck error: '-' is empty.
>
> Any idea what is wrong?

At the very least the tests are using -march=arm and then checking for
ELF-specific objdumping. Fixing that will probably make the weird
assertion failure go away too, though it could be something more
substantial.

Cheers.

Tim.