SuperCall incorrectly tolerated in constructors of classes with no lineage

[jugglinmike]

As of version 2.12.0, JSHint incorrectly allows SuperCall expression to appear in the constructor function of classes which do not define a lineage.

For example, the following text contains a syntax error, but JSHint does not recognize it:

/* jshint esversion: 6 */
class C {
  constructor() {
    super();
  }
}

[nicolo-ribaudo]

There is this old PR I opened: #2572

There are conflicts in every file it touches so probably it's easier for someone to open a new one rather than trying to rebase my PR, but there might be some useful review comments or ideas in the code.

[jugglinmike]

Thanks, @nicolo-ribaudo! That's some memory you've got :)