test: augment the SDK sysroot for Windows

Windows does not have `intptr_t` and `uintptr_t` defined properly.
Define the types using the clang builtin types in the SDK.

Author: compnerd

test/Inputs/clang-importer-sdk/usr/include/ctypes.h

@@ -170,6 +170,10 @@ typedef SInt32 OSStatus;
 
 // Types from stdint.h.
 #include <stdint.h>
+#if defined(_WIN32)
+typedef __INTPTR_TYPE__ intptr_t;
+typedef __UINTPTR_TYPE__ uintptr_t;
+#endif
 STDLIB_TEST(__UINT8_TYPE__, uint8_t);
 STDLIB_TEST(__UINT16_TYPE__, uint16_t);
 STDLIB_TEST(__UINT32_TYPE__, uint32_t);