Summary
-------
Update core libraries for JDK 26 by adding an enum constant to `ClassFileFormatVersion` and a constant to `ClassFile`.

Problem
-------

With a new release, `ClassFileFormatVersion` and `ClassFile` need a constants to model that release.

Solution
--------

Add the new constants.

Specification
-------------

    diff --git a/src/java.base/share/classes/java/lang/classfile/ClassFile.java b/src/java.base/share/classes/java/lang/classfile/ClassFile.java
    index 4b529c39099..216facbdddf 100644
    --- a/src/java.base/share/classes/java/lang/classfile/ClassFile.java
    +++ b/src/java.base/share/classes/java/lang/classfile/ClassFile.java
    @@ -1030,6 +1030,14 @@ default List<VerifyError> verify(Path path) throws IOException {
          */
         int JAVA_25_VERSION = 69;
     
    +    /**
    +     * The class major version introduced by Java SE 26, {@value}.
    +     *
    +     * @see ClassFileFormatVersion#RELEASE_26
    +     * @since 26
    +     */
    +    int JAVA_26_VERSION = 70;
    +
         /**
          * A minor version number {@value} indicating a class uses preview features
          * of a Java SE release since 12, for major versions {@value
    @@ -1041,7 +1049,7 @@ default List<VerifyError> verify(Path path) throws IOException {
          * {@return the latest class major version supported by the current runtime}
          */
         static int latestMajorVersion() {
    -        return JAVA_25_VERSION;
    +        return JAVA_26_VERSION;
         }
     
         /**
    diff --git a/src/java.base/share/classes/java/lang/reflect/ClassFileFormatVersion.java b/src/java.base/share/classes/java/lang/reflect/ClassFileFormatVersion.java
    index 70eb921a124..4a63dd157f8 100644
    --- a/src/java.base/share/classes/java/lang/reflect/ClassFileFormatVersion.java
    +++ b/src/java.base/share/classes/java/lang/reflect/ClassFileFormatVersion.java
    @@ -371,6 +371,18 @@ public enum ClassFileFormatVersion {
          * <cite>The Java Virtual Machine Specification, Java SE 25 Edition</cite></a>
          */
         RELEASE_25(69),
    +
    +    /**
    +     * The version introduced by the Java Platform, Standard Edition
    +     * 26.
    +     *
    +     * @since 26
    +     *
    +     * @see <a
    +     * href="https://docs.oracle.com/javase/specs/jvms/se26/html/index.html">
    +     * <cite>The Java Virtual Machine Specification, Java SE 26 Edition</cite></a>
    +     */
    +    RELEASE_26(70),
         ; // Reduce code churn when appending new constants
     
         // Note to maintainers: when adding constants for newer releases,
    @@ -386,7 +398,7 @@ private ClassFileFormatVersion(int major) {
          * {@return the latest class file format version}
          */
         public static ClassFileFormatVersion latest() {
    -        return RELEASE_25;
    +        return RELEASE_26;
         }
     
         /**