Several tests fail to compile classes when java.util.Optional is a value class.

Modify java.util.Optional to be a value class and build.
The following tests fail with the message below:

tools/javac/annotations/repeatingAnnotations/combo/TargetAnnoCombo.java
tools/javac/classfiles/attributes/innerclasses/InnerClassesInInnerEnumTest.java
tools/javac/classfiles/attributes/innerclasses/InnerClassesTest.java
tools/javac/jvm/VerboseClassPathTest.java

 bad class file: /modules/java.base/java/util/Optional.class
    method descriptor invalid for <init>