Refactor - IDL class def

[b-ma]

Some heavy work and JS black magic to make more idlharness tests pass

$ npm run wpt:only -- --filter idlharness
RESULTS (before):
  - # pass: 632
  - # fail: 511
  - # type error issues: 0
  
RESULTS (after):
  - # pass: 871
  - # fail: 272
  - # type error issues: 0

Impact on overall wpt is interesting too (unlocked quite a few tests :)

$ npm run wpt
RESULTS (before):
  - # pass: 6240
  - # fail: 1072
  - # type error issues: 24

RESULTS (after):
  - # pass: 6739
  - # fail: 800
  - # type error issues: 24

[orottier]

Alright, I don't understand everything but the results are solid!

[orottier]

I'm very surprised we need to check this inside the class AnalyserNode?
Also, instanceof works with inheritance properly right? So if a user has MyNode extends AnalyserNode these methods are still callable?

[b-ma]

Ah yup I was a bit surprised too at first... but actually it makes sens since this is always possible to try to execute anything with the this you want in JS, e.g. this is the test which is made in the idlharness (warning it can hurt you eyes :):

const desc = Object.getOwnPropertyDescriptor(AnalyserNode.prototype, 'fftSize');
desc.set.call({}, 256);

Also, instanceof works with inheritance properly right. So if a user has MyNode extends AnalyserNode these methods are still callable?

Yup it should, which is nice