Try beefier mac on integration tests

Author: alan-george-lk

.github/workflows/tests.yml

@@ -45,11 +45,8 @@ jobs:
         include:
           - os: ubuntu-latest
             name: linux-x64
-          - os: ubuntu-24.04-arm
-            name: linux-arm64
           # macos-latest currently maps to a lower-spec 3-core/7GB arm64 image;
-          # macos-26 gives us 4 cores/14GB on the standard free runner tier.
-          - os: macos-26
+          - os: macos-latest-xlarge
             name: macos-arm64
 
     name: Test (${{ matrix.name }})