[msan] Fix name_to_handle_at test on overlayfs.

Udev supports name_to_handle_at. Use /dev/null instead of /bin/cat.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@354402 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed