java/beans/XMLEncoder/java_awt_ScrollPane.java failed with `java.awt.HeadlessException` on Mac

java/beans/XMLEncoder/java_awt_ScrollPane.java failed with `java.awt.HeadlessException` on Mac.

```
Stacktrace
Execution failed: `main' threw exception: java.awt.HeadlessException: The application is not running in a desktop session, but this program performed an operation which requires it.
Standard Output

Standard Error
java.awt.HeadlessException:
The application is not running in a desktop session,
but this program performed an operation which requires it.
...

JavaTest Message: Test threw exception: java.awt.HeadlessException:
The application is not running in a desktop session,
but this program performed an operation which requires it.
JavaTest Message: shutting down test

STATUS:Failed.`main' threw exception: java.awt.HeadlessException: The application is not running in a desktop session, but this program performed an operation which requires it.
```
https://ci.adoptopenjdk.net/view/Test_openjdk/job/Test_openjdk16_hs_extended.openjdk_x86-64_mac_testList_1/10/testReport/java_beans_XMLEncoder_java_awt_ScrollPane/java/java_awt_ScrollPane/

Start with java/beans/XMLEncoder/java_awt_ScrollPane.java and the linked CI test report to reproduce the java.awt.HeadlessException on Mac. Determine the test's expected behavior in a non-desktop session and verify that the test completes successfully without this failure.

Written by the indexing model from the issue text.