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.
diff --git a/src/testdir/dumps/Test_smooth_wrap_5.dump b/src/testdir/dumps/Test_smooth_wrap_5.dump
new file mode 100644
index 0000000..04a17f9
--- /dev/null
+++ b/src/testdir/dumps/Test_smooth_wrap_5.dump
@@ -0,0 +1,8 @@
+>L+0&#ffffff0|i|n|e| |w|i|t|h| |s|o|m|e| |t|e|x|t| |w|i|t|h| |s|o|m|e| |t|e|x|t| |w|i|t|h| 
+|s|o|m|e| |t|e|x|t| |w|i|t|h| |s|o|m|e| |t|e|x|t| |w|i|t|h| |s|o|m|e| |t|e|x|t| 
+|w|i|t|h| |s|o|m|e| |t|e|x|t| |w|i|t|h| |s|o|m|e| |t|e|x|t| @10
+|L|i|n|e| |w|i|t|h| |s|o|m|e| |t|e|x|t| |w|i|t|h| |s|o|m|e| |t|e|x|t| |w|i|t|h| 
+|s|o|m|e| |t|e|x|t| |w|i|t|h| |s|o|m|e| |t|e|x|t| |w|i|t|h| |s|o|m|e| |t|e|x|t| 
+|w|i|t|h| |s|o|m|e| |t|e|x|t| |w|i|t|h| |s|o|m|e| |t|e|x|t| @10
+|@+0#4040ff13&@2| @36
+| +0#0000000&@21|5|,|1| @10|8|0|%| 
diff --git a/src/testdir/test_scroll_opt.vim b/src/testdir/test_scroll_opt.vim
index d11d0be..0292fa1 100644
--- a/src/testdir/test_scroll_opt.vim
+++ b/src/testdir/test_scroll_opt.vim
@@ -181,6 +181,7 @@
 
   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', {})
 
@@ -190,6 +191,10 @@
   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