Adding support for more engines/runtimes

The list of JS engines is well-known and very long. eshost does not gatekeep, support for any JS engine or runtime ("host") may be added as long as a reasonable subset of the eshost runtime can be implemented. Issues merely requesting a new host are of little value and will be closed unless they contain additional context required to implement the eshost integration.

Experience from test262.fyi has shown that these kinds of integrations inevitably bitrot and considerably increase maintenance cost. This is not surprising as neither CLI flags nor host-specific APIs required to implement the eshost runtime are usually considered stable. For this reason adding a new host comes with the implied responsibility of maintaining the integration going forward. Failure to do so may result in subsequent removal of the host.

Start with the linked eshost runtime library and review the existing host integrations to identify the runtime entry points and required CLI or host APIs. The issue names no specific engine, files, or tests; done would mean a justified host integration covering a reasonable runtime subset and an ongoing maintenance commitment.