Add --watch flag to other subcommands

[bartlomieju]

deno run --watch was added in #7382.

Now we should work towards adding the same flag to other subcommands:

• bundle
• fmt
• lint
• test

Each of the subcommands might require a bit different approach as not all of them work using ModuleGraph.

We might also want to refactor file_watcher not to create a new watcher after each restart.

[bartlomieju]

This is mostly implemented, still missing deno lint --watch, but let's continue in #11132