need flag to enable `CompilerOptions.setAssumeStaticInheritanceRequired(true)`

[brad4d]

To avoid compilation breaking uses of this and super in static methods of ES6 classes, you have to get CommandLineRunner to do CompilerOptions.setAssumeStaticInheritanceRequired(true) when creating the Compiler object.

Unfortunately, there is no flag for this yet, and we can't make it the default behavior because of increase in output code size it causes for Google projects.

This would be a good community-volunteer thing to do.

[cshung]

@brad4d I am interested in this one.

[brad4d]

@cshung thanks for your interest. We'll look out for a PR from you.

[adiroy05]

i can also do it