Fix test to actually check the FixIt-applied code

r102230 added an 'echo' making this a no-op.

Also fixes FAIL on native Windows with no shell/GnuWin32.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@193938 91177308-0d34-0410-b5e6-96231b3b80d8