patch 9.0.1018: suspend test still fails on Mac OS

Problem:    Suspend test still fails on Mac OS.
Solution:   Make 'keyprotocol' empty.
diff --git a/src/testdir/test_suspend.vim b/src/testdir/test_suspend.vim
index ab1a091..ef8fea5 100644
--- a/src/testdir/test_suspend.vim
+++ b/src/testdir/test_suspend.vim
@@ -22,9 +22,9 @@
   CheckFeature terminal
   CheckExecutable /bin/sh
 
-  " Somehow the modifyOtherKeys response may get to the terminal when using Mac
-  " OS.  Make t_RK empty to avoid that.
-  set t_RK=
+  " Somehow the modifyOtherKeys response may get to the terminal when using
+  " Mac OS.  Make t_RK and 'keyprotocol' empty to avoid that.
+  set t_RK= keyprotocol=
 
   call WaitForResponses()
 
@@ -72,9 +72,9 @@
   CheckFeature terminal
   CheckExecutable /bin/sh
 
-  " Somehow the modifyOtherKeys response may get to the terminal when using Mac
-  " OS.  Make t_RK empty to avoid that.
-  set t_RK=
+  " Somehow the modifyOtherKeys response may get to the terminal when using
+  " Mac OS.  Make t_RK and 'keyprotocol' empty to avoid that.
+  set t_RK= keyprotocol=
 
   call WaitForResponses()