convert JDWP agent to CPP

[alexmenkov]

---

Progress

• [ ] Change must be properly reviewed (1 review required, with at least 1 Reviewer)
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• [ ] Commit message must refer to an issue

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Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk.git pull/28838/head:pull/28838
$ git checkout pull/28838

Update a local copy of the PR:
$ git checkout pull/28838
$ git pull https://git.openjdk.org/jdk.git pull/28838/head

Using Skara CLI tools

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$ git pr checkout 28838

View PR using the GUI difftool:
$ git pr show -t 28838

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Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/28838.diff

[bridgekeeper[bot]]

:wave: Welcome back amenkov! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk[bot]]

❗ This change is not yet ready to be integrated. See the Progress checklist in the description for automated requirements.

[openjdk[bot]]

@alexmenkov The following label will be automatically applied to this pull request:

• serviceability

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