RFR: 8292911: Add a note about jtreg failure handlers in the testing doc [v3]

[Erik Joelsson]

On Fri, 26 Aug 2022 13:48:54 GMT, Jaikiran Pai <jpai at openjdk.org> wrote:

>> Can I please get a review of this change to the testing documentation which adds a note about failure handlers in jtreg? This addresses https://bugs.openjdk.org/browse/JDK-8292911.
>> 
>> Recently, there have been users who have been prompted for sudo password when running jtreg tests locally and those tests running into failures. This is because one of the commands that gets executed by the jtreg failure handler uses sudo (the `sudo dmesg` command on macos).
>> 
>> This commit updates the `testing.md` to explain what the failure handler does and also mentions the configuration that can be used to disable the failure handler. This commit doesn't specify how to configure the `sudoers` file if the user still wants to allow the failure handlers to run, because I thought that would be outside the scope of this documentation.
>> 
>> I attempted to auto generate the `testing.html` from the changes to `testing.md` using the `make update-build-docs` command, but that generated a lot of unnecessary diffs not just in `testing.html` but other html files in the `doc` directory. So, as suggested in a different PR which involved updates to these files, I manually added the section to the `testing.html` too.
>
> Jaikiran Pai has updated the pull request incrementally with one additional commit since the last revision:
> 
>   fix line length

Marked as reviewed by erikj (Reviewer).

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PR: https://git.openjdk.org/jdk/pull/10021