[ADT] Fix a test case to use a correct escape for a null byte followed
by a valid octal digit.

The length argument shows that this was in fact the intent.

This was pointed out in IRC, thanks to eddyb!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@307496 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed