buildkite: run "Release tests" on amd64

This test fails on arm64:
ERROR: vdso/BUILD:12:8: Executing genrule //vdso:vdso failed: (Exit 1):
bash failed: error executing command /bin/bash -c ...

Use --sandbox_debug to see verbose messages from the sandbox
gcc: error: unrecognized command line option '-m64'
Target //runsc:runsc failed to build
PiperOrigin-RevId: 449398920

.buildkite/pipeline.yaml

@@ -111,6 +111,8 @@ steps:
       - make BAZEL_OPTIONS=--config=x86_64 artifacts/x86_64
       - make BAZEL_OPTIONS=--config=aarch64 artifacts/aarch64
       - make release
+    agents:
+      arch: "amd64"
 
   # Images tests.
   - <<: *common
@@ -224,6 +226,7 @@ steps:
     label: ":docker: Containerd 1.3.9 tests"
     command: make containerd-test-1.3.9
     agents:
+      cgroup: "v1"
       arch: "amd64"
       os: "ubuntu"
   - <<: *common