[SHLWAPI] Improvements for SHCreateWorkerWindowW/A() prototypes + fix x64-bit compati...

[SHLWAPI] Improvements for SHCreateWorkerWindowW/A() prototypes + fix x64-bit compatibility. Sent upstream.

[SHLWAPI] Refactor the SHCreateWorkerWindowW() prototype to match its ANSI SHCreateWorkerWindowA() counterpart.

The last parameter is really to be understood as an extra window data, and not a "message result" (as it would be the case for dialog window procedure).
That is why I also remove the mention of "DWLP_MSGRESULT" in the SetWindowLongPtrW() call.
SHCreateWorkerWindowA() had it OK but SHCreateWorkerWindowW() did not.

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[SHLWAPI] Make SHCreateWorkerWindowA() and SHCreateWorkerWindowW() x64-compatible.

The first parameter of these functions is a pointer to a window procedure, having a definite prototype, so employ a correct typedef WNDPROC,
which ensures both correct pointer size and parameter type enforcement.
This also ensures that we use instead a correct pointer size, since otherwise LONG remains 32-bits for Windows compatibility on x64 platforms.
The wndProc parameter is thus casted to LONG_PTR to comply with the SetWindowLongPtrA/W calls.

In SHCreateWorkerWindowW(), the last "wnd_extra" parameter should also be LONG_PTR to be able to pass 64-bit data pointer on x64 platforms.
Therefore fix also setting the wc.cbWndExtra size. One should note that the ANSI SHCreateWorkerWindowA() function had everything OK already.