Merge pull request #213573 from Homebrew/arm64-builds

workflows/tests: set `HOMEBREW_ARM64_TESTING`

Author: carlocab

.github/workflows/tests.yml

@@ -15,6 +15,7 @@ env:
   HOMEBREW_TEST_BOT_ANALYTICS: 1
   HOMEBREW_ENFORCE_SBOM: 1
   HOMEBREW_NO_BUILD_ERROR_ISSUES: 1
+  HOMEBREW_ARM64_TESTING: 1
   GH_REPO: ${{github.repository}}
   GH_NO_UPDATE_NOTIFIER: 1
   GH_PROMPT_DISABLED: 1