Javac regression test tools/javac/T8003967/DetectMutableStaticFields.java failing

The test is failing with:
There is a mutable field named NONENCODING_CHARS, at class com/sun/tools/doclets/formats/html/markup/HtmlTree
java.lang.AssertionError: There are mutable fields, please check output
at DetectMutableStaticFields.run(DetectMutableStaticFields.java:149)
at DetectMutableStaticFields.main(DetectMutableStaticFields.java:123)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:491)
at com.sun.javatest.regtest.MainAction$SameVMRunnable.run(MainAction.java:746)
at java.lang.Thread.run(Thread.java:724)