RFR: 8297791: update _max_classes in NodeClasses

[Matthijs Bijman]

Updates _max_classes to reflect the newly introduced LShift node from JDK-8259609

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Commit messages:
 - 8297791: update _max_classes in NodeClasses

Changes: https://git.openjdk.org/jdk/pull/11669/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=11669&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8297791
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/11669.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11669/head:pull/11669

PR: https://git.openjdk.org/jdk/pull/11669