[analyzer] Allow egraph rewriter not to open the generated HTML directly (#85515)

When developing on a headless device through SSH, we do not have a
browser or even an X environment. Hence, it would be more convenient if
the rewriter could stop before attempting to open the generated HTML
file. Then, it can be opened remotely through an HTML server.

This patch adds a new option `--dump-html-only` to make the rewriter
stop before opening the generated HTML in a browser. The new option is
marked in conflict with the existing `--dump-dot-only` option to prevent
unexpected behaviors.