JCK 11 test classfmt/cpl/cplidc005/cplidc00501m018/cplidc00501m018.html was written for JEP 309.
It's used to test the following assertions:
Chapter 4.4.10
name_and_type_index
  In a CONSTANT_Dynamic_info structure, the indicated descriptor must be a field descriptor (4.3.2).[jvms-4.4.10-200-C.1]
 In a CONSTANT_InvokeDynamic_info structure, the indicated descriptor must be a method descriptor (4.3.3).[jvms-4.4.10-200-C.2]

The test case cplidc00501m018 is negative and uses the method descriptor "<init>":"(Ljava/lang/String;)Z" to get
java.lang.ClassFormatError: Method "<init>" in class <NAME> has illegal signature "(Ljava/lang/String;)Z"

The test was correct for versions JDK 11-17, now it fails with JDK 18, 19 because no exceptions are thrown.