Support case where win32socketserver's window class is not unregistered properly.
Support case where win32socketserver's window class is not unregistered properly.

Either from failure to shutdown or when instantiated in a dll that is loaded or
unloaded multiple times within a single process lifetime.

Change-Id: I52b05a6d84c9312fbd45aaa34ed3f49566daadfd
Bug: b/140961297
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/155987
Commit-Queue: Tommi <74a97831ec830b6e3846c6faa50560947ae01c68@webrtc.org>
Reviewed-by: Tommi <74a97831ec830b6e3846c6faa50560947ae01c68@webrtc.org>
Reviewed-by: Mirko Bonadei <d2c43c210eae6feef04f53bae50885e8152edcca@webrtc.org>
Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#29574}

TimothyGu/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc