[AVR] Remove some accidentally-commited code that broke the bots

This is a remnant of an on-chip unit testing tool that has since been
moved out-of-tree.

It was accidentally committed in r287162.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@287180 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed