Tidy up annotations in timedetector, etc.

Platform annotations like @Nullable / @NonNull are not TYPE_USE
annotations. Move usages on fields to before access modifiers for
consistency.

@IntDef / @StringDef can apparently be TYPE_USE and TYPE_PARAMETER, so
switch to using them as such. Also fix retention policy at the same
time.

Bug: 165832200
Test: compiler only (treehugger)
Change-Id: I621ea50d09262807963a8a74c3838ff1b516bc26