patch 9.1.0786: tests: quickfix update test does not test location list

Problem:  tests: quickfix update test does not test location list
          (after: v9.1.0.785)
Solution: update Test_quickfix_buffer_contents to test with location
          lists (Yegappan Lakshmanan)

closes: #15879

Signed-off-by: Yegappan Lakshmanan <yegappan@yahoo.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/testdir/test_quickfix.vim b/src/testdir/test_quickfix.vim
index c611ce8..c382e68 100644
--- a/src/testdir/test_quickfix.vim
+++ b/src/testdir/test_quickfix.vim
@@ -6462,7 +6462,9 @@
   call setqflist([], 'f')
 endfunc
 
-func Test_quickfix_update()
+func XquickfixUpdateTests(cchar)
+  call s:setup_commands(a:cchar)
+
   " Setup: populate a couple buffers
   new
   call setline(1, range(1, 5))
@@ -6472,25 +6474,32 @@
   let b2 = bufnr()
   " Setup: set a quickfix list.
   let items = [{'bufnr': b1, 'lnum': 1}, {'bufnr': b1, 'lnum': 2}, {'bufnr': b2, 'lnum': 1}, {'bufnr': b2, 'lnum': 2}]
-  call setqflist(items)
+  call g:Xsetlist(items)
 
   " Open the quickfix list, select the third entry.
-  copen
+  Xopen
   exe "normal jj\<CR>"
-  call assert_equal(3, getqflist({'idx' : 0}).idx)
+  call assert_equal(3, g:Xgetlist({'idx' : 0}).idx)
 
   " Update the quickfix list. Make sure the third entry is still selected.
-  call setqflist([], 'u', { 'items': items })
-  call assert_equal(3, getqflist({'idx' : 0}).idx)
+  call g:Xsetlist([], 'u', { 'items': items })
+  call assert_equal(3, g:Xgetlist({'idx' : 0}).idx)
 
   " Update the quickfix list again, but this time with missing line number
   " information. Confirm that we keep the current buffer selected.
-  call setqflist([{'bufnr': b1}, {'bufnr': b2}], 'u')
-  call assert_equal(2, getqflist({'idx' : 0}).idx)
+  call g:Xsetlist([{'bufnr': b1}, {'bufnr': b2}], 'u')
+  call assert_equal(2, g:Xgetlist({'idx' : 0}).idx)
+
+  Xclose
 
   " Cleanup the buffers we allocated during this test.
   %bwipe!
-  %bwipe!
+endfunc
+
+" Test for updating a quickfix list using the "u" flag in setqflist()
+func Test_quickfix_update()
+  call XquickfixUpdateTests('c')
+  call XquickfixUpdateTests('l')
 endfunc
 
 func Test_quickfix_update_with_missing_coordinate_info()
diff --git a/src/version.c b/src/version.c
index 7345bd5..06a52a0 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    786,
+/**/
     785,
 /**/
     784,