This bug is a follow-up to the CR feedback at https://chromium-review.googlesource.com/c/chromium/src/+/1222684/2/content/browser/web_contents/web_contents_impl.cc#5950

We should split WebContentsImpl::ShouldIgnoreUnresponsiveRenderer into

1) ShouldIgnoreTimeoutsInRenderer
   (to be used via RVHDelegate from
    RenderViewHostImpl::ClosePageTimeout and
    RenderFrameHostImpl::BeforeUnloadTimeout)

2) ShouldIgnoreUnresponsiveRenderer
   (to be used from WebContentsImpl::RendererUnresponsive)