P12SecretKey.java creates test*.test files in the default system temp directory:

cat -n jdk/test/sun/security/pkcs12/P12SecretKey.java
  [...]
    66 File ksFile = File.createTempFile("test", ".test");

These files are not cleaned up at the end of the run.

The preferred approach would be to create temporary test directories and files under the jtreg property user.dir instead, if it is defined.