[Libomptarget][NFC] Remove trivially true checks on function pointers (#86804)

Summary:
Previously we had an interface that checked these functions pointers to
see if they are implemented by the plugin. This was removed as currently
every single function is implemented as a part of the common interface.
These checks are now always true and do nothing.
GitOrigin-RevId: 4a5056be2e38bdf27125a41f3f1b7ae4233f9713
3 files changed