[PSDK][REACTOS] Fix definitions and usage of DWLP_MSGRESULT, DWLP_DLGPROC, and DWLP_USER - Make sure the DWLP_* values are correct on _WIN64 - Don't use the DWL_* constants, they are not portable. Enforce this by removing them entirely from winuser.h - Make sure Get/SetWindowLong*Ptr* is used and pointers are not truncated to LONG master