Fix Go installation and benchmark tests for Apple Silicon

[paulmaunders]

Description

This PR addresses the Rosetta errors encountered when running Go benchmarks on Apple Silicon Macs. It modifies the benchmark Dockerfile to install the correct architecture-specific version of Go and adds tmp.benchmarks to .gitignore.

Changes

• Added architecture detection in Dockerfile to install correct Go binary:
  • Uses arm64 version on Apple Silicon/aarch64
  • Uses amd64 version on x86_64
• Added tmp.benchmarks to .gitignore to avoid committing benchmark results

Testing

• Verified on Apple Silicon Mac:
  • Dockerfile now downloads correct arm64 Go binary
  • Go tests run without Rosetta errors
  • Benchmarks complete successfully

Problem

Previously on Apple Silicon Macs, Go tests would fail with:

rosetta error: Rosetta is only intended to run on Apple Silicon with a macOS host using Virtualization.framework with Rosetta mode enabled

This was because the wrong architecture (x86_64) Go binary was being installed.

[paul-gauthier]

Thanks for trying aider and filing this PR.

The benchmark is intended to be run inside the docker container. Are you experiencing this problem when running it that way?

[paulmaunders]

Yes, I'm running the benchmark inside the docker container on my Macbook M3

[paul-gauthier]

I see, thanks for the fix.