[MWRAPPER-155] add jabbaw to mvnw

**[Stephan Kölle](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=JIRAUSER284103)** opened **[MWRAPPER-155](https://issues.apache.org/jira/browse/MWRAPPER-155?redirect=false)** and commented

The developer build stability provided by `mvnw` is excellent, and I’d like to suggest a small enhancement that aligns with its convenience.

By adding the following snippet to the `mvnw` script:

```java
if [ -f ./.jabbarc ] && [ -f ./jabbaw ]; then
export $(./jabbaw env | grep JAVA_HOME)
fi
```

 
 
This integrates with https://github.com/Jabba-Team/jabba, specifically its "install-less" variant https://github.com/Jabba-Team/jabba/blob/main/jabbaw.md  to define a JDK version via the `.jabbarc` configuration file.

This addition would make it easy to ensure a consistent JDK setup directly from the `mvnw` script, which could be particularly useful for teams or projects requiring precise JDK versioning without additional manual setup.

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**Affects:** 3.3.2