svm: no longer need to substitute TypeVariableImpl on JDK latest [JDK-8345565]

Author: zapster

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/hub/SunReflectTypeSubstitutions.java

@@ -29,8 +29,9 @@
 import com.oracle.svm.core.annotate.Alias;
 import com.oracle.svm.core.annotate.Substitute;
 import com.oracle.svm.core.annotate.TargetClass;
+import com.oracle.svm.core.jdk.JDK21OrEarlier;
 
-@TargetClass(sun.reflect.generics.reflectiveObjects.TypeVariableImpl.class)
+@TargetClass(value = sun.reflect.generics.reflectiveObjects.TypeVariableImpl.class, onlyWith = JDK21OrEarlier.class)
 final class Target_sun_reflect_generics_reflectiveObjects_TypeVariableImpl {
 
     @Alias GenericDeclaration genericDeclaration;