Adding a vector version of clang::tooling::shiftedCodePosition().

During the transition of clang::tooling::Replacements from std::set to
std::vector, functions such as clang::tooling::applyAllReplacements() have been
duplicated to take a std::vector<Replacement>. Applying this same temporary
duplication to clang::tooling::shiftedCodePosition().

llvm-svn: 189358