[libc] fix string conversion tests for windows

There were some copy paste errors as well as some oddities around how
windows handles the difference between long and long long types. This
change fixes those.

Reviewed By: sivachandra

Differential Revision: https://reviews.llvm.org/D108591

GitOrigin-RevId: 1d02a8bcd393ea9c50f0212797059888efc78002
5 files changed