Since jtreg 7.x requires Java 11 to we should replacereflective code to access API from Java 11 and former releases.
For example: `pidMethod = Process.class.getDeclaredMethod("pid"); // only available in Java 9+` as discussed in https://github.com/openjdk/jtreg/pull/215#pullrequestreview-2241473245
For example: `pidMethod = Process.class.getDeclaredMethod("pid"); // only available in Java 9+` as discussed in https://github.com/openjdk/jtreg/pull/215#pullrequestreview-2241473245