CanWriteSequence.java and WriteAfterAbort.java are creating files in the system default temp directory:
% cat -n jdk/test/javax/imageio/plugins/shared/CanWriteSequence.java jdk/test/javax/imageio/plugins/shared/WriteAfterAbort.java | grep createTemp
57 final File file = File.createTempFile("temp", ".img");
68 final File file = File.createTempFile("temp", ".img");
These files are left behind, even though the tests also set file.deleteOnExit():
The preferred approach would be to create temporary test directories and files under the jtreg property test.dir instead, if it is defined.