patch 8.0.0692: CTRL-G with 'incsearch' and ? goes in the wrong direction

Problem:    Using CTRL-G with 'incsearch' and ? goes in the wrong direction.
            (Ramel Eshed)
Solution:   Adjust search_start. (Christian Brabandt)
diff --git a/src/testdir/test_search.vim b/src/testdir/test_search.vim
index 18a4577..69b1335 100644
--- a/src/testdir/test_search.vim
+++ b/src/testdir/test_search.vim
@@ -322,3 +322,37 @@
   call test_override("char_avail", 0)
   bw!
 endfunc
+
+func Test_search_cmdline4()
+  if !exists('+incsearch')
+    return
+  endif
+  " need to disable char_avail,
+  " so that expansion of commandline works
+  call test_override("char_avail", 1)
+  new
+  call setline(1, ['  1 the first', '  2 the second', '  3 the third'])
+  set incsearch
+  $
+  call feedkeys("?the\<c-g>\<cr>", 'tx')
+  call assert_equal('  3 the third', getline('.'))
+  $
+  call feedkeys("?the\<c-g>\<c-g>\<cr>", 'tx')
+  call assert_equal('  1 the first', getline('.'))
+  $
+  call feedkeys("?the\<c-g>\<c-g>\<c-g>\<cr>", 'tx')
+  call assert_equal('  2 the second', getline('.'))
+  $
+  call feedkeys("?the\<c-t>\<cr>", 'tx')
+  call assert_equal('  1 the first', getline('.'))
+  $
+  call feedkeys("?the\<c-t>\<c-t>\<cr>", 'tx')
+  call assert_equal('  3 the third', getline('.'))
+  $
+  call feedkeys("?the\<c-t>\<c-t>\<c-t>\<cr>", 'tx')
+  call assert_equal('  2 the second', getline('.'))
+  " clean up
+  set noincsearch
+  call test_override("char_avail", 0)
+  bw!
+endfunc