RFR: 8359707: Add classfile modification code to RedefineClassHelper [v2]

[Coleen Phillimore]

> I copied this code for another test in the Valhalla repo and thought it would be a good utility function.  It might be better written using the Classfile API.
> Tested with test.

Coleen Phillimore has updated the pull request incrementally with one additional commit since the last revision:

  Add a byte buffer version and rename parameters.

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Changes:
  - all: https://git.openjdk.org/jdk/pull/25857/files
  - new: https://git.openjdk.org/jdk/pull/25857/files/3654034f..6bc1ca59

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=25857&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=25857&range=00-01

  Stats: 23 lines in 1 file changed: 13 ins; 2 del; 8 mod
  Patch: https://git.openjdk.org/jdk/pull/25857.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25857/head:pull/25857

PR: https://git.openjdk.org/jdk/pull/25857