Fix detection of super statement in visiting constructor

[frodi-karlsson]

Fixes #540

[jakebailey]

This would probably benefit from an emit test (see the neighboring file for this transform),

[frodi-karlsson]

@microsoft-github-policy-service agree

[frodi-karlsson]

For some more context:

• If there are no parameters, we return early on L804.
• The nodes before pushing the constructor are { current: Parameter, parent: ClassDeclaration }
• Pushing the constructor yields the class declaration, which we should then check for classness and all that

[jakebailey]

This to me seems like the evidence that this change is right.

[jakebailey]

Checked with @rbuckton and there's apparently another cause to this.

[jakebailey]

Checked with @rbuckton and there's apparently another cause to this.

[rbuckton]

There are two issues at play here. One is that visit has an early return when visiting modifiers on parameters and fails to call popNode, the other is that we don't need to call pushNode(constructor) in transformConstructorBody

[rbuckton]

I've put up the fix for these issues in #679