Incorrect removal of parentheses

[zhantx]

Closure compiler removes parentheses from class declaration rendering the output code to be illegal input

let _Component;
class Component {}
class P extends (_Component = Component) {}

output

'use strict';
let _Component;
class Component {
}
class P extends _Component = Component {
}
;

The assignment at supercalss must have parentheses

[brad4d]

@dloyda is working on this.

[dloyda]

Fixed by https://github.com/google/closure-compiler/commit/5a20d7dc12cf9acad8c84e3fe4e2bf10dec3ed0e