The sv ud literal was added to C++17 for creating string_views, but
the Clang we have doesn't know that so it warns about using a
reserved ud literal name. Disable the warning since it's not
important here anyway.
Test: ./run_tests.py
Bug: http://b/34740564
Change-Id: I7b59a4b63969252d4df012df3c11d7638cbfa5a0