Use make_range(rbegin(), rend()) to allow foreach loops. NFC.

Use make_range(rbegin(), rend()) to allow foreach loops.  NFC.

Instead of the pattern

for (auto I = x.rbegin(), E = x.end(); I != E; ++I)

we can use make_range to construct the reverse range and iterate using
that instead.

llvm-svn: 243163