RFR: 8364346: Typo in IR framework README

[Tobias Hartmann]

On Wed, 8 Oct 2025 10:50:43 GMT, Lei Zhu <duke at openjdk.org> wrote:

> Fix typo errors.

As the bug report describes, the duplicated `-DExcludeRandom=true` in the README should be removed as well.

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Changes requested by thartmann (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/27688#pullrequestreview-3314273531