patch 8.0.0394: tabs are not aligned when scrolling horizontally

Problem:    Tabs are not aligned when scrolling horizontally and a Tab doesn't
            fit. (Axel Bender)
Solution:   Handle a Tab as a not fitting character. (Christian Brabandt)
            Also fix that ":redraw" does not scroll horizontally to show the
            cursor.  And fix the test that depended on the old behavior.
diff --git a/src/testdir/test_breakindent.vim b/src/testdir/test_breakindent.vim
index 8721b35..7deffbe 100644
--- a/src/testdir/test_breakindent.vim
+++ b/src/testdir/test_breakindent.vim
@@ -274,7 +274,6 @@
 
 function Test_breakindent16()
   " Check that overlong lines are indented correctly.
-  " TODO: currently it does not fail even when the bug is not fixed.
   let s:input=""
   call s:test_windows('setl breakindent briopt=min:0 ts=4')
   call setline(1, "\t".repeat("1234567890", 10))
@@ -283,16 +282,16 @@
   redraw!
   let lines=s:screen_lines(1,10)
   let expect=[
-\ "    123456",
 \ "    789012",
 \ "    345678",
+\ "    901234",
 \ ]
   call s:compare_lines(expect, lines)
   let lines=s:screen_lines(4,10)
   let expect=[
-\ "    901234",
 \ "    567890",
 \ "    123456",
+\ "    7890  ",
 \ ]
   call s:compare_lines(expect, lines)
   call s:close_windows()