test: Increase determinism in screen_basic_spec tests

test/functional/ui/screen.lua

@@ -259,6 +259,13 @@ This is probably due to an indeterminism in the test. Try adding
 `wait()` (or even a separate `screen:expect(...)`) at a point of possible
 indeterminism, typically in between a `feed()` or `execute()` which is non-
 synchronous, and a synchronous api call.
+
+Note that sometimes a `wait` can trigger redraws and consequently generate more
+indeterminism. If adding `wait` calls seems to increase the frequency of these
+messages, try removing every `wait` call in the test.
+
+If everything else fails, use Screen:redraw_debug to help investigate what is
+  causing the problem.
       ]])
     local tb = debug.traceback()
     local index = string.find(tb, '\n%s*%[C]')

test/functional/ui/screen_basic_spec.lua

@@ -488,7 +488,6 @@ describe('Screen', function()
     end)
 
     it('has minimum width/height values', function()
-      wait()
       screen:try_resize(1, 1)
       screen:expect([[
         -- INS^ERT --|