fix: vm,使用tostring将浮点数输出成字符串时,会出现多余的空格,丢失小数点

https://gitee.com/openLuat/LuatOS/issues/IBN9TN

关联起一个相关的提交 bf1d4dec1f80eb3b873b6dc205ff02e19c7f8b14

当前是把这部分代码改成直接格式化, 写的格式化字符串是 %9g, 应该写 %.9g,

现改回lua自带的格式化字符串

Signed-off-by: Wendal Chen <wendal1985@gmail.com>

lua/src/lauxlib.c

@@ -851,7 +851,7 @@ LUALIB_API const char *luaL_tolstring (lua_State *L, int idx, size_t *len) {
         }
         else {
           n = (LUAI_UACNUMBER)lua_tonumber(L, idx);
-          sprintf_(buff, "%9g", n);
+          sprintf_(buff, LUA_NUMBER_FMT, n);
           lua_pushstring(L, buff);
         }
         break;