Windows build broke from recent Unicode changes -- need to #define

SIZEOF_SHORT by hand here.
Also added dynamic check that SIZEOF_SHORT is correct for the platform (in
_testcapimodule).

Modules/_testcapimodule.c

@@ -52,6 +52,7 @@ test_config(PyObject *self, PyObject *args)
 	    if (FATNAME != sizeof(TYPE)) \
     	    	return sizeof_error(#FATNAME, #TYPE, FATNAME, sizeof(TYPE))
 
+	CHECK_SIZEOF(SIZEOF_SHORT, short);
 	CHECK_SIZEOF(SIZEOF_INT, int);
 	CHECK_SIZEOF(SIZEOF_LONG, long);
 	CHECK_SIZEOF(SIZEOF_VOID_P, void*);

PC/config.h

@@ -344,6 +344,7 @@ typedef unsigned long uintptr_t;
 #define Py_DEBUG
 #endif
 
+#define SIZEOF_SHORT 2
 #define SIZEOF_INT 4
 #define SIZEOF_LONG 4
 #define SIZEOF_LONG_LONG 8