extension_ci: Increase runners for tests job (#47686)

We were hitting some timeout failures with some runners, hence bumping
the size here.

Release Notes:

- N/A

.github/workflows/extension_tests.yml

@@ -51,7 +51,7 @@ jobs:
     needs:
     - orchestrate
     if: needs.orchestrate.outputs.check_rust == 'true'
-    runs-on: namespace-profile-4x8-ubuntu-2204
+    runs-on: namespace-profile-8x16-ubuntu-2204
     steps:
     - name: steps::checkout_repo
       uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
@@ -74,7 +74,7 @@ jobs:
       shell: bash -euxo pipefail {0}
       env:
         NEXTEST_NO_TESTS: warn
-    timeout-minutes: 3
+    timeout-minutes: 6
   check_extension:
     needs:
     - orchestrate

tooling/xtask/src/tasks/workflows/extension_tests.rs

@@ -48,8 +48,8 @@ fn run_clippy() -> Step<Run> {
 fn check_rust() -> NamedJob {
     let job = Job::default()
         .with_repository_owner_guard()
-        .runs_on(runners::LINUX_MEDIUM)
-        .timeout_minutes(3u32)
+        .runs_on(runners::LINUX_LARGE)
+        .timeout_minutes(6u32)
         .add_step(steps::checkout_repo())
         .add_step(steps::cache_rust_dependencies_namespace())
         .add_step(steps::cargo_fmt())