patch 8.2.2707: adding a lot of completions can still be a bit slow

Problem:    Adding a lot of completions can still be a bit slow.
Solution:   Add the check for CP_FAST. (Ben Jackson)
diff --git a/src/insexpand.c b/src/insexpand.c
index 8f10866..9bbf123 100644
--- a/src/insexpand.c
+++ b/src/insexpand.c
@@ -586,7 +586,10 @@
     int		dir = (cdir == 0 ? compl_direction : cdir);
     int		flags = flags_arg;
 
-    ui_breakcheck();
+    if (flags & CP_FAST)
+	fast_breakcheck();
+    else
+	ui_breakcheck();
     if (got_int)
 	return FAIL;
     if (len < 0)