hack jython tests to work on windows

windows needs access to the "root" holding the jar file (see https://github.com/int3/jython/blob/master/src/org/python/core/PySystemState.java#L571-L616)

Its different on windows, because when canonicalizing the file (case sensitivity), it needs access to the file.

Closes #13476

core/src/test/java/org/elasticsearch/bootstrap/BootstrapForTesting.java

@@ -97,6 +97,7 @@ public class BootstrapForTesting {
                     String filename = path.getFileName().toString();
                     if (filename.contains("jython") && filename.endsWith(".jar")) {
                         // just enough so it won't fail when it does not exist
+                        perms.add(new FilePermission(path.getParent().toString(), "read,readlink"));
                         perms.add(new FilePermission(path.getParent().resolve("Lib").toString(), "read,readlink"));
                     }
                 }