vim-patch:9.0.0673: first line wong with 'smoothscroll' and 'scrolloff' zero

Problem:    First line not scrolled properly with 'smoothscroll' and
            'scrolloff' zero and using "k".
Solution:   Make sure the cursor position is visible.

46b54747c5

Co-authored-by: Bram Moolenaar <Bram@vim.org>

test/functional/legacy/scroll_opt_spec.lua

@@ -307,7 +307,7 @@ describe('smoothscroll', function()
     screen:try_resize(40, 8)
     exec([[
       call setline(1, ['Line' .. (' with some text'->repeat(7))]->repeat(7))
-      set smoothscroll scrolloff=0
+      set smoothscroll scrolloff=0 display=
       :3
     ]])
     screen:expect([[
@@ -322,9 +322,22 @@ describe('smoothscroll', function()
     ]])
     feed('j')
     screen:expect_unchanged()
+    -- moving cursor down - whole bottom line shows
     feed('<C-E>j')
     screen:expect_unchanged()
     feed('G')
     screen:expect_unchanged()
+    -- moving cursor up - whole top line shows
+    feed('2k')
+    screen:expect([[
+      ^Line with some text with some text with |
+      some text with some text with some text |
+      with some text with some text           |
+      Line with some text with some text with |
+      some text with some text with some text |
+      with some text with some text           |
+      @                                       |
+                                              |
+    ]])
   end)
 end)

test/old/testdir/test_scroll_opt.vim

@@ -198,6 +198,7 @@ func Test_smoothscroll_wrap_scrolloff_zero()
 
   call VerifyScreenDump(buf, 'Test_smooth_wrap_1', {})
 
+  " moving cursor down - whole bottom line shows
   call term_sendkeys(buf, "j")
   call VerifyScreenDump(buf, 'Test_smooth_wrap_2', {})
 
@@ -207,6 +208,10 @@ func Test_smoothscroll_wrap_scrolloff_zero()
   call term_sendkeys(buf, "G")
   call VerifyScreenDump(buf, 'Test_smooth_wrap_4', {})
 
+  " moving cursor up - whole top line shows
+  call term_sendkeys(buf, "2k")
+  call VerifyScreenDump(buf, 'Test_smooth_wrap_5', {})
+
   call StopVimInTerminal(buf)
 endfunc