RFR: 7903426: jcstress: Polish README.md [v2]

[Aleksey Shipilev]

On Thu, 2 Feb 2023 13:09:27 GMT, Johnny Lim <duke at openjdk.org> wrote:

>> This PR polishes the `README.md` file a bit.
>
> Johnny Lim has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Apply suggestions

Good. Say `/integrate`.

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Marked as reviewed by shade (Committer).

PR: https://git.openjdk.org/jcstress/pull/131