dead code: Remove useless resize calls.

We had a bunch of places where we
were calling `resize.resize_bottom_whitespace`
with no arguments, which has been a no-op
since the below commit that removed support
for our `autoscroll_forever` option:

    fa44d2ea69

With the `autoscroll_forever` options things
like opening/closing the compose box could
alter how much bottom whitespace you'd want,
but we stopped supporting that feature in
2017.

Since then bottom_whitespace has just always
been 40% of the viewport size.  So we only need
to change it on actual resize events.

It's worth noting that we still call
`resize_bottom_whitespace` indirectly in many
places, via `resize_page_components`, and
the latter actually causes
`resize_bottom_whitespace` to do real work,
but that work is redundant for most of those
codepaths, since they're not triggered by
changes to the viewport.  So there are other
opportunities for cleanup.

frontend_tests/node_tests/compose.js

@@ -22,9 +22,6 @@ const _document = {
 const _drafts = {
     delete_draft_after_send: noop,
 };
-const _resize = {
-    resize_bottom_whitespace: noop,
-};
 
 const _sent_messages = {
     start_tracking_message: noop,
@@ -42,7 +39,6 @@ set_global('drafts', _drafts);
 set_global('navigator', _navigator);
 set_global('notifications', _notifications);
 set_global('reminder', _reminder);
-set_global('resize', _resize);
 set_global('sent_messages', _sent_messages);
 
 set_global('local_message', {});
@@ -52,6 +48,7 @@ set_global('stream_edit', {});
 set_global('markdown', {});
 set_global('loading', {});
 set_global('page_params', {});
+set_global('resize', {});
 set_global('subs', {});
 set_global('ui_util', {});
 

frontend_tests/node_tests/compose_actions.js

@@ -63,10 +63,6 @@ set_global('drafts', {
     update_draft: noop,
 });
 
-set_global('resize', {
-    resize_bottom_whitespace: noop,
-});
-
 set_global('narrow_state', {
     set_compose_defaults: noop,
 });

frontend_tests/node_tests/message_fetch.js

@@ -35,7 +35,6 @@ set_global('notifications', {
     hide_or_show_history_limit_message: () => {},
 });
 set_global('pm_list', {});
-set_global('resize', {});
 set_global('server_events', {});
 set_global('stream_list', {
     maybe_scroll_narrow_into_view: () => {},
@@ -48,7 +47,6 @@ const alice = {
 };
 people.add_active_user(alice);
 
-resize.resize_bottom_whitespace = noop;
 server_events.home_view_loaded = noop;
 
 function stub_message_view(list) {