Ensure acceptance test artifacts are being built for correct arch (#18079)

* Ensure acceptance test artifacts are being built for correct arch

With the improvment in #17995 we only
build packages that match the architecture of the host. This is specified with
an enviornment variable. Previously the acceptance tests did not need to
specifcy the architecture when building packages. This commit updates the
builder to build packages with the correct arch.

* Ensure ARCH is set for docker acceptance tests

Author: donoghuc

.buildkite/aarch64_pipeline.yml

@@ -133,7 +133,7 @@ steps:
       - label: "Docker [{{matrix}}] flavor acceptance"
         command:
           set -euo pipefail
-          
+          export ARCH="aarch64"
           source .buildkite/scripts/common/vm-agent.sh && ci/docker_acceptance_tests.sh {{matrix}}
         retry:
           automatic:

.buildkite/scripts/exhaustive-tests/generate-steps.py

@@ -125,6 +125,7 @@ def acceptance_linux_steps() -> list[typing.Any]:
 source .buildkite/scripts/common/vm-agent.sh
 echo "--- Building all artifacts"
 ./gradlew clean bootstrap
+export ARCH="x86_64"
 rake artifact:deb artifact:rpm
 """),
         "artifact_paths": [
@@ -162,6 +163,7 @@ def acceptance_docker_steps()-> list[typing.Any]:
             "command": LiteralScalarString(f"""#!/usr/bin/env bash
 set -euo pipefail
 source .buildkite/scripts/common/vm-agent.sh
+export ARCH="x86_64"
 ci/docker_acceptance_tests.sh {flavor}"""),
             "retry": {"automatic": [{"limit": 3}]},
         })