[clang-tidy] Made abseil-upgrade-duration-conversions tests pass on c++17

Summary: Made abseil-upgrade-duration-conversions tests pass on c++17

Reviewers: hokein, gribozavr

Reviewed By: gribozavr

Subscribers: xazax.hun, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D63262

Patch by Johan Vikström.

llvm-svn: 363270