patch 8.2.4929: off-by-one error in in statusline item

Problem:    Off-by-one error in in statusline item.
Solution:   Subtrace one less. (closes #10394, closes #5599)
diff --git a/src/testdir/test_statusline.vim b/src/testdir/test_statusline.vim
index eaf1525..7c75f61 100644
--- a/src/testdir/test_statusline.vim
+++ b/src/testdir/test_statusline.vim
@@ -469,7 +469,6 @@
   call writefile(lines, 'XTest_statusline')
 
   let buf = RunVimInTerminal('-S XTest_statusline', {'rows': 10, 'cols': 50})
-  call TermWait(buf, 50)
   call VerifyScreenDump(buf, 'Test_statusline_1', {})
 
   " clean up
@@ -541,4 +540,22 @@
   bwipe!
 endfunc
 
+func Test_statusline_highlight_truncate()
+  CheckScreendump
+
+  let lines =<< trim END
+    set laststatus=2
+    hi! link User1 Directory
+    hi! link User2 ErrorMsg
+    set statusline=%.5(%1*ABC%2*DEF%1*GHI%)
+  END
+  call writefile(lines, 'XTest_statusline')
+
+  let buf = RunVimInTerminal('-S XTest_statusline', {'rows': 6})
+  call VerifyScreenDump(buf, 'Test_statusline_hl', {})
+
+  call StopVimInTerminal(buf)
+  call delete('XTest_statusline')
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab