Fix printf warnings on Windows

[saghul]

D:\a\quickjs\quickjs\quickjs.c(1439,20): warning C4777: 'printf' : format string '%llu' requires an argument of type 'unsigned __int64', but variadic argument 1 has type 'size_t' [D:\a\quickjs\quickjs\build\qjs.vcxproj]
      D:\a\quickjs\quickjs\quickjs.c(1439,20):
      the sizes of types 'size_t' and 'unsigned __int64' might differ on other platforms
      D:\a\quickjs\quickjs\quickjs.c(1439,20):
      consider using '%zu' in the format string