[jdk11u-dev] RFR: 8315863: [GHA] Update checkout action to use v4

[Christoph Langer]

On Wed, 20 Sep 2023 09:15:42 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> Semi-clean backport to improve GHA reliability. It does not apply cleanly, because the relevant block for GTest acquisition is missing in 11u.
> 
> Additional testing:
>  - [ ] GHA

Marked as reviewed by clanger (Reviewer).

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PR Review: https://git.openjdk.org/jdk11u-dev/pull/2135#pullrequestreview-1635648141