vim-patch:8.2.0614: get ml_get error when deleting a line in 'completefunc' (#19244)

Problem:    Get ml_get error when deleting a line in 'completefunc'. (Yegappan
            Lakshmanan)
Solution:   Lock the text while evaluating 'completefunc'.
ff06f283e3

Fix a mistake in the porting of patch 8.1.0098.
Cherry-pick Test_run_excmd_with_text_locked() from patch 8.2.0270.
Cherry-pick test_gf.vim changes from patch 8.2.0369.
Cherry-pick message change from later patches.

src/nvim/match.c

@@ -494,10 +494,10 @@ static void next_search_hl(win_T *win, match_T *search_hl, match_T *shl, linenr_
       shl->lnum += shl->rm.startpos[0].lnum;
       break;                            // useful match found
     }
-
-    // Restore called_emsg for assert_fails().
-    called_emsg = save_called_emsg;
   }
+
+  // Restore called_emsg for assert_fails().
+  called_emsg = save_called_emsg;
 }
 
 /// Advance to the match in window "wp" line "lnum" or past it.