RFR: 8355652: Parse ClassFileFormatVersion from ClassFileVersion

[simon]

8355652: add new method to return ClassFileFormatVersion from ClassFileVersion.
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### Progress
- [ ] Change must be properly reviewed (1 review required, with at least 1 [Reviewer](https://openjdk.org/bylaws#reviewer))
- [x] Change must not contain extraneous whitespace
- [x] Commit message must refer to an issue

### Error
 ⚠️ The pull request body must not be empty.

### Integration blocker
 ⚠️ Title mismatch between PR and JBS for issue [JDK-8355652](https://bugs.openjdk.org/browse/JDK-8355652)

### Warning
 ⚠️ Found trailing period in issue title for `8355652: add new method to return ClassFileFormatVersion from ClassFileVersion.`
Found leading lowercase letter in issue title for `8355652: add new method to return ClassFileFormatVersion from ClassFileVersion.`



### Reviewing
<details><summary>Using <code>git</code></summary>

Checkout this PR locally: \
`$ git fetch https://git.openjdk.org/jdk.git pull/26406/head:pull/26406` \
`$ git checkout pull/26406`

Update a local copy of the PR: \
`$ git checkout pull/26406` \
`$ git pull https://git.openjdk.org/jdk.git pull/26406/head`

</details>
<details><summary>Using Skara CLI tools</summary>

Checkout this PR locally: \
`$ git pr checkout 26406`

View PR using the GUI difftool: \
`$ git pr show -t 26406`

</details>
<details><summary>Using diff file</summary>

Download this PR as a diff file: \
<a href="https://git.openjdk.org/jdk/pull/26406.diff">https://git.openjdk.org/jdk/pull/26406.diff</a>

</details>

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Commit messages:
 - 8355652: add new method to return ClassFileFormatVersion from ClassFileVersion.

Changes: https://git.openjdk.org/jdk/pull/26406/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=26406&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8355652
  Stats: 17 lines in 2 files changed: 17 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/26406.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26406/head:pull/26406

PR: https://git.openjdk.org/jdk/pull/26406