MSVC C26800 warned us std::vector and std::string are not guaranteed to
be cleared after being moved from in all standard C++ implementations.
As we reuse those objects and rely they are cleared, do an explicit
clear. We could have one-time-use objects and add scopes, but that makes
code ugly.
Reference: https://stackoverflow.com/a/17735913/2071884
Signed-off-by: Simon Rozman <simon@rozman.si>
