Generated equals may not override `Any#equals`

Some libraries, in this case `js-joda`, declare their equals methods as taking (TypeScript) `any`. This results in the Kotlin stub function `override fun equals(other: Any): Boolean`, however this doesn't actually override `Any#equals` which is defined as nullable: `fun equals(other: Any?): Boolean`. I think the correct behavior here would be to emit `other: Any?` in the stub, since TypeScript's `any` type may be null/undefined as well.

Start by tracing how TypeScript `any` is mapped to Kotlin parameter types and where generated `equals` declarations are emitted. Reproduce the conversion for the `js-joda` declarations, then verify that the generated signature uses nullable `Any?` and correctly overrides Kotlin `Any#equals`.

Written by the indexing model from the issue text.