Remove OatFileAssistant IsOutOfDate, IsUpToDate, and NeedsRelocation.

Relatively recent design changes made these functions equivalent to
the Status function. Prefer to use the Status function instead to
simplify the OatFileAssistant API, especially in preparation for
expanding the number of possible Status results.

Bug: 30937355
Test: oat_file_assistant_test

Change-Id: Idfd594729210257f693f03ca823a8d54e74034c5
3 files changed