patch 9.0.2046: win32,python: warning that MS_WIN64 got re-defined

Problem:  win32,python: warning that MS_WIN64 got re-defined
Solution: Do not define MS_WIN64, as it is no longer used

Suppress the following warning:
```
In file included from C:/Python312-64/include/Python.h:12,
                 from if_python3.c:79:
C:/Python312-64/include/pyconfig.h:240: warning: "MS_WIN64" redefined
  240 | #define MS_WIN64
      |
<command-line>: note: this is the location of the previous definition
```

`MS_WIN64` is not defined in `Make_mvc.mak` either.
This should be able to be safely removed.

closes: #13370

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: Ken Takata <kentkt@csc.jp>

src/Make_cyg_ming.mak

@@ -513,9 +513,6 @@ endif # RUBY
 DEF_GUI=-DFEAT_GUI_MSWIN -DFEAT_CLIPBOARD
 DEFINES=-DWIN32 -DWINVER=$(WINVER) -D_WIN32_WINNT=$(WINVER) \
 	-DHAVE_PATHDEF -DFEAT_$(FEATURES) -DHAVE_STDINT_H
-ifeq ($(ARCH),x86-64)
-DEFINES+=-DMS_WIN64
-endif
 
 #>>>>> end of choices
 ###########################################################################

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2046,
 /**/
     2045,
 /**/