Update cl::opt<uint64_t> instances to cl::opt<unsigned long long>

cl::opt<uint64_t> fails when parsing command line arguments.

See https://bugs.llvm.org/show_bug.cgi?id=19665.

Reviewers: pcc

Subscribers: mgorny, llvm-commits, kcc

Differential Revision: https://reviews.llvm.org/D38657

llvm-svn: 317141