正则表达式中 \ 也会被吞

对于正则表达式的 \d 等符号也会丢失，有什么通用的方法解决转义符号丢失的问题吗

```java
REPLACEREG("xxx4ch", '(\d*)ch', "中间包第$1炉")
```

```java
public class ReplaceRegOperator extends Operator {

@Override
public Object executeInner(Object[] list) throws Exception {
if (list == null) {
return "";
}
if (list.length < 3) {
return list[0];
}
return ReUtil.replaceAll((CharSequence) list[0], (String) list[1], (String) list[2]);
}
}
```

Start at ReplaceRegOperator.executeInner and trace the ReUtil.replaceAll call using the supplied Java expression '(\d*)ch'. Reproduce where the backslash is lost and define a regression case for preserving \d and replacement $1; done means the regular expression reaches replacement handling without losing its escape.

Written by the indexing model from the issue text.