RFR: 8340831: Simplify simple validation for class definition in MethodHandles.Lookup

[Chen Liang]

`MethodHandles.Lookup` defines a `ClassFile` for simple validations; it is unnecessary and can be scalarized manually. The removal of `ClassFile` class is also slightly helpful for bootstrap by reducing class loading. Also improved class file version checking in `VM` class.

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Commit messages:
 - 8340831: Simplify simple validation for class definition in MethodHandles.Lookup

Changes: https://git.openjdk.org/jdk/pull/21170/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=21170&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8340831
  Stats: 136 lines in 2 files changed: 19 ins; 58 del; 59 mod
  Patch: https://git.openjdk.org/jdk/pull/21170.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21170/head:pull/21170

PR: https://git.openjdk.org/jdk/pull/21170