Original commit message:

    [debug] Fix crash when pausing in for-of loop header

    Given a for-of loop:

      for (const each of subject) {

    The bytecode generator emits the iterator.next call + done check +
    assigning to `each` all into the source position of `const each`.

    The pseudo-desugared code looks something like:

      var tmp;
      loop {
        var result = iterator.next();
        if (result.done) break;
        tmp = result.value;

        PushBlockContext;
        const each = tmp;

        // rest of the loop.
      }

    This is a problem, as the parser starts the block scope already on
    the `const each`. If the scope requires a context we can pause on
    bytecode that has or has not pushed the block context yet, while
    the source position looks the same.

    The recent addition of per-script unique scope IDs lets us fix
    this problem in the debugger: We can check if the scope ID of
    the runtime scope matches the parser scope. If not, the context
    was not pushed yet.

    The debugger already has a `HasContext` helper. We extend it to
    also check for matching scope IDs and then use `HasContext` where
    we would read variable values off the context. If the context was
    not pushed yet, we report them as 'unavailable'.

    R=leszeks@chromium.org

    Fixed: 384413079,399002824
    Change-Id: Ia2d0008d574e7eaf6c06b640053df696014d37f8
    Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/6507402
    Reviewed-by: Leszek Swirski <leszeks@chromium.org>
    Commit-Queue: Simon Zünd <szuend@chromium.org>
    Cr-Commit-Position: refs/heads/main@{#100029}

Refs: v8/v8@5ba9200
Fixes: #60580
PR-URL: #60620
Signed-off-by: Juan José Arboleda <soyjuanarbol@gmail.com>