1. the `primitive == object?.something` fusion should not apply to
`primitive.equals(object?.something)` because it can't;
2. coercions to Int are there for a reason - don't remove them;
3. better optimize `primitive == object?.something` -- the result
should be subject to if-null fusion, so it needs to have a specific
pattern that resembles safe calls.
#KT-47597 Fixed
In code like 'a?.b == 42', we can immediately generate equality
comparison result when receiver is null (false for '==', true for '!='),
since the primitive value is definitely non-null.
Otherwise unnecessary boxing/unboxing is generated to handle possibly
null result of 'a?.b'.