java/awt/Paint/ListRepaint.java intermittently fails due to NullPointerException

FULL PRODUCT VERSION :
java version "1.8.0_161"
Java(TM) SE Runtime Environment (build 1.8.0_161-b12)
Java HotSpot(TM) 64-Bit Server VM (build 25.161-b12, mixed mode)


ADDITIONAL OS VERSION INFORMATION :
Linux unit-959 4.13.0-37-generic #42-Ubuntu SMP Wed Mar 7 14:13:23 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

A DESCRIPTION OF THE PROBLEM :
The test java/awt/Paint/ListRepaint.java intermittently fails due to NullPointerException on Ubuntu 17.10. The issue was not observed on Windows, macOS.
Reproducibility ~20%

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
failed=0
count=0
while [ ${failed} -eq 0 ]
do
  jtreg -ignore:quiet -v -a -xml \
      -exclude:exclude.tests \
      -testjdk:"$TESTJDK" \
      -javaoptions:"-Djava.awt.headless=false -Xms128m -Xmx750m -XX:ReservedCodeCacheSize=240m -XX:+UseCompressedOops" \
      -timeoutFactor:2 java/awt/Paint
  failed=$?
  count=$((count+1))
  echo "${count}. failed=${failed}"
done

where exclude.tests contained:

java/awt/Paint/PaintNativeOnUpdate.java
java/awt/Paint/bug8024864.java


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
No exceptions expected
ACTUAL -
NullPointerException is thrown

ERROR MESSAGES/STACK TRACES THAT OCCUR :
#section:main
----------messages:(4/136)----------
command: main ListRepaint
reason: Assumed action based on file name: run main ListRepaint
Mode: othervm
elapsed time (seconds): 12.478
----------configuration:(0/0)----------
----------System.out:(0/0)----------
----------System.err:(22/1170)----------
java.lang.NullPointerException
at sun.awt.X11.XListPeer$ListPainter.paintFocus(XListPeer.java:1998)
at sun.awt.X11.XListPeer$ListPainter.paint(XListPeer.java:1850)
at sun.awt.X11.XListPeer$ListPainter.access$000(XListPeer.java:1701)
at sun.awt.X11.XListPeer.repaint(XListPeer.java:411)
at sun.awt.X11.XListPeer.repaint(XListPeer.java:386)
at sun.awt.X11.XListPeer.repaint(XListPeer.java:382)
at sun.awt.X11.XListPeer.select(XListPeer.java:1234)
at java.awt.List.select(List.java:571)
at ListRepaint.test(ListRepaint.java:73)
at ListRepaint.main(ListRepaint.java:51)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:115)
at java.lang.Thread.run(Thread.java:748)

JavaTest Message: Test threw exception: java.lang.NullPointerException
JavaTest Message: shutting down test

STATUS:Failed.`main' threw exception: java.lang.NullPointerException


REPRODUCIBILITY :
This bug can be reproduced occasionally.

---------- BEGIN SOURCE ----------
http://hg.openjdk.java.net/jdk8u/jdk8u/jdk/file/f940e7a48b72/test/java/awt/Paint/ListRepaint.java
---------- END SOURCE ----------