Fix Errors.h on systems that define NO_ERROR

Some systems (originally only Windows) define their own
NO_ERROR macro that overlaps with the enumerator from Errors.h.
The enumerator is only defined if the macro was not.

Bug: 224644083
Test: m
Change-Id: Iee0932b5259b3bfcf6494656b27e6e7488319f5c