Don't double-initialize cl::opt for iterating in reverse order to uncover...

Don't double-initialize cl::opt for iterating in reverse order to uncover non-determinism in codegen by default

Bots are broken and needs to be fixed before having this on by default.
The feature was committed in r289619.

I tried to disable it in r289624 and failed because it was initialized in two places.

llvm-svn: 289626