patch 8.2.0047: cannot skip tests for specific MS-Windows platform

Problem:    Cannot skip tests for specific MS-Windows platform.
Solution:   Add windowsversion().
diff --git a/src/evalfunc.c b/src/evalfunc.c
index 892a753..610eca4 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -276,6 +276,7 @@
 static void f_virtcol(typval_T *argvars, typval_T *rettv);
 static void f_visualmode(typval_T *argvars, typval_T *rettv);
 static void f_wildmenumode(typval_T *argvars, typval_T *rettv);
+static void f_windowsversion(typval_T *argvars, typval_T *rettv);
 static void f_wordcount(typval_T *argvars, typval_T *rettv);
 static void f_xor(typval_T *argvars, typval_T *rettv);
 
@@ -864,6 +865,7 @@
     {"win_splitmove",   2, 3, FEARG_1,    f_win_splitmove},
     {"winbufnr",	1, 1, FEARG_1,	  f_winbufnr},
     {"wincol",		0, 0, 0,	  f_wincol},
+    {"windowsversion",	0, 0, 0,	  f_windowsversion},
     {"winheight",	1, 1, FEARG_1,	  f_winheight},
     {"winlayout",	0, 1, FEARG_1,	  f_winlayout},
     {"winline",		0, 0, 0,	  f_winline},
@@ -8408,6 +8410,16 @@
 }
 
 /*
+ * "windowsversion()" function
+ */
+    static void
+f_windowsversion(typval_T *argvars UNUSED, typval_T *rettv UNUSED)
+{
+    rettv->v_type = VAR_STRING;
+    rettv->vval.v_string = vim_strsave((char_u *)windowsVersion);
+}
+
+/*
  * "wordcount()" function
  */
     static void