[github] Use pre-installed swift version

The marketplace GitHub action for checking out a specific swift version
causes all kinds of issues.
While installing swift manually is possible, it's extra work. As the
default GitHub ubuntu container ships with swift 6.2 pre-installed,
switch to just using that version.
Note: The MacOS instance uses 6.1.2 which is also new enough for our
purposes.

This allows us to reland commit 80ad045.

Fixed: 448848874
Change-Id: I28fa83b07c3f49dcdd6ef45dbac838d7ebeb885e
Reviewed-on: https://chrome-internal-review.googlesource.com/c/v8/fuzzilli/+/8687278
Reviewed-by: Michael Achenbach <[email protected]>
Commit-Queue: Michael Achenbach <[email protected]>
Auto-Submit: Matthias Liedtke <[email protected]>

Author: Liedtke

.github/workflows/swift.yml

@@ -26,9 +26,6 @@ jobs:
       - uses: actions/setup-node@v4
         with:
           node-version: 25-nightly
-      - uses: swift-actions/setup-swift@v2
-        with:
-          swift-version: "6.0.3"
       - name: Swift Version
         run: swift --version
       - uses: actions/checkout@v2