patch 9.1.0050: Win32 Keyboard handling is sub-optimal

Problem:  Win32 Keyboard handling is sub-optimal and has
          many issues with international keyboards
          (risa2000) (after v8.2.4807)
Solution: soft-rollback the change, allow the user to select
          a suitable key-translation strategy
          (Anton Sharonov)

Read about the details in the help:
    :h w32-experimental-keycode-trans-strategy

fixes: #10615
fixes: #12595
closes: #12752

Signed-off-by: Anton Sharonov <anton.sharonov@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/testing.c b/src/testing.c
index 1835643..0d731da 100644
--- a/src/testing.c
+++ b/src/testing.c
@@ -1539,7 +1539,7 @@
 	rettv->vval.v_number = test_gui_find_repl(argvars[1].vval.v_dict);
 #  endif
 #  ifdef MSWIN
-    else if (STRCMP(event, "key") == 0 || STRCMP(event, "mouse") == 0)
+    else if (STRCMP(event, "key") == 0 || STRCMP(event, "mouse") == 0 || STRCMP(event, "set_keycode_trans_strategy") == 0)
 	rettv->vval.v_number = test_mswin_event(event, argvars[1].vval.v_dict);
 #  endif
     else if (STRCMP(event, "mouse") == 0)