Skip backward_compatibility and query_fuzz tests on ARM64

These tests fail on ARM64 runners and should only execute on AMD64:

## integration_backward_compatibility

Old Cortex versions (v1.13.1, v1.13.2, v1.14.0) were released before
ARM64 support was added in v1.14.1 and do not have ARM64 Docker images.

When Docker attempts to run these amd64-only images on ARM64 runners via
QEMU emulation, they crash with a fatal Go runtime error:
  "runtime: lfstack.push invalid packing ... fatal error: lfstack.push"

This is a known issue with Go binaries and QEMU emulation (golang/go#69255).

While v1.14.1+ versions do have ARM64 images, skipping the entire test
on ARM64 is simpler and sufficient since backward compatibility testing
validates protocol compatibility, which is architecture-agnostic.

## integration_query_fuzz

This fuzzy testing suite compares query results between Cortex v1.18.1
and the current version. Although v1.18.1 has ARM64 support, the test
produces inconsistent results on ARM64 (NaN value mismatches), likely
due to floating-point arithmetic differences between architectures.

## Testing Coverage

All other ARM64 integration tests (6 test suites) pass successfully:
- requires_docker
- integration_alertmanager
- integration_memberlist
- integration_querier
- integration_ruler
- integration_remote_write_v2

This provides comprehensive validation of modern Cortex functionality
on ARM64 architecture while avoiding known compatibility issues with
historical testing scenarios.

Fixes #6897

Signed-off-by: thc1006 <[email protected]>

Author: thc1006

.github/workflows/test-build-deploy.yml

@@ -188,9 +188,6 @@ jobs:
           - runner: ubuntu-24.04-arm
             arch: arm64
             tags: integration_alertmanager
-          - runner: ubuntu-24.04-arm
-            arch: arm64
-            tags: integration_backward_compatibility
           - runner: ubuntu-24.04-arm
             arch: arm64
             tags: integration_memberlist
@@ -200,9 +197,6 @@ jobs:
           - runner: ubuntu-24.04-arm
             arch: arm64
             tags: integration_ruler
-          - runner: ubuntu-24.04-arm
-            arch: arm64
-            tags: integration_query_fuzz
           - runner: ubuntu-24.04-arm
             arch: arm64
             tags: integration_remote_write_v2