Add some missing nullability annotations in SQLiteDatabase

Align param docs with annotations.
selectionArgs, whereArgs, nullColumnHack should be nullable.
table and sql should be nonnull.
Also tag values, initialValues accordingly.
Annotated return values.

Fixes: 264142524
Test: N/A
Change-Id: Ic660f7ba8d3b135b45efb48a73a5e7487cbb18ca