BREAKING CHANGE: Make class fields a special kind of property

[dcodeIO]

Removes the hard distinction between fields, i.e.

class Foo {
  a: i32;
}

and properties, i.e.

class Foo {
  get a(): i32 { return 42; }
  set a(value: i32) { }
}

by making fields special kinds of properties, differing in having an associated memory offset. As a result, fields (which get built-in getters and setters) and properties (with explicit getters and setters) can override each other, lifting the annoying limitation that interface fields can only be implemented with properties. Since interchangeable fields and properties are more powerful than what is possible in JS/TS, compatibility with TS becomes a matter of disallowing what wouldn't be supported there due to JS nature.

• I've read the contributing guidelines
• I've added my name and email to the NOTICE file

[dcodeIO]

Last commit bakes in static instanceof helpers for both classes and interfaces that no longer rely on the RTTI blob. Together with host bindings that also generate static code, bundling the RTTI blob now is no longer necessary. I did not yet remove the RTTI blob, since doing so in turn renders the loader non-functional, so should likely get its own PR.

[dcodeIO]

(for some reason this one doesn't show as merged as usual but is still open, so closing manually)