I've run the jtreg tests on JDK 18 macos ARM 6 times and every time the first 3 of these tests failed and 5 / 6 times the final test failed.

javax/swing/JButton/8151303/PressedIconTest.java
java/awt/FullScreen/FullScreenInsets/FullScreenInsets.java
java/awt/Dialog/MakeWindowAlwaysOnTop/MakeWindowAlwaysOnTop.java
java/awt/Frame/MiscUndecorated/RepaintTest.java

The logs and screenshots don't tell me much at all.
But it is clear we should problem list for macosx-aarch64 so that we can run these tests during CI without lots of noise.

There are existing bugs for macos relating to all of these 3 of them specific to these tests on this exact platform reporting that they fail sometimes.
I find they fail "usually" but I don't have an array of systems on which to test.
But on balance they are all likely test instability issues and I think most of
them are problem listed on other platforms already.

Bugs against we can problem list :-
https://bugs.openjdk.java.net/browse/JDK-8252813 (all except Repaint test)
https://bugs.openjdk.java.net/browse/JDK-8266246 - specific about PressedIconTest on mac arm
https://bugs.openjdk.java.net/browse/JDK-8266245 - FullScreenInsets.java
https://bugs.openjdk.java.net/browse/JDK-8266244 - RepaintTest.java