[Bug 28738] user32/tests: invalid read in server_end_to_end_callback in dde.ok?

https://bugs.winehq.org/show_bug.cgi?id=28738

--- Comment #4 from Austin English  ---
Still in git:
==6245== Invalid read of size 2
==6245==    at 0x4D1E4E8: wine_dbgstr_wn (test.h:486)
==6245==    by 0x4C3B542: wine_dbgstr_w (test.h:69)
==6245==    by 0x4C49657: server_end_to_end_callback (dde.c:2465)
==6245==    by 0x50BE856: WDML_InvokeCallback (dde_misc.c:1231)
==6245==    by 0x50C3762: WDML_ServerHandleExecute (dde_server.c:834)
==6245==    by 0x50C3D2E: WDML_ServerHandle (dde_server.c:1002)
==6245==    by 0x50C42A4: WDML_ServerConvProc (dde_server.c:1112)
==6245==    by 0x514B4DD: ??? (winproc.c:173)
==6245==    by 0x514B652: call_window_proc (winproc.c:244)
==6245==    by 0x514D8A1: WINPROC_call_window (winproc.c:909)
==6245==    by 0x510E8CD: DispatchMessageA (message.c:3948)
==6245==    by 0x4C4A6A8: test_end_to_end_server (dde.c:2675)
==6245==    by 0x4C4AB15: func_dde (dde.c:2741)
==6245==    by 0x4D1EA14: run_test (test.h:584)
==6245==    by 0x4D1EE03: main (test.h:654)
==6245==  Address 0x4725f08 is 16 bytes inside a block of size 17 alloc'd
==6245==    at 0x7BC4C735: notify_alloc (heap.c:255)
==6245==    by 0x7BC50F79: RtlAllocateHeap (heap.c:1716)
==6245==    by 0x4C495A1: server_end_to_end_callback (dde.c:2461)
==6245==    by 0x50BE856: WDML_InvokeCallback (dde_misc.c:1231)
==6245==    by 0x50C3762: WDML_ServerHandleExecute (dde_server.c:834)
==6245==    by 0x50C3D2E: WDML_ServerHandle (dde_server.c:1002)
==6245==    by 0x50C42A4: WDML_ServerConvProc (dde_server.c:1112)
==6245==    by 0x514B4DD: ??? (winproc.c:173)
==6245==    by 0x514B652: call_window_proc (winproc.c:244)
==6245==    by 0x514D8A1: WINPROC_call_window (winproc.c:909)
==6245==    by 0x510E8CD: DispatchMessageA (message.c:3948)
==6245==    by 0x4C4A6A8: test_end_to_end_server (dde.c:2675)
==6245==    by 0x4C4AB15: func_dde (dde.c:2741)
==6245==    by 0x4D1EA14: run_test (test.h:584)
==6245==    by 0x4D1EE03: main (test.h:654)
==6245==