ruby-immutable-ruby: : FTBFS with glibc 2.39 snapshot

[Ravi Kant Sharma]

During the recent test rebuilds, one of the rebuild configurations was against a snapshot of the upcoming glibc 2.39.

ruby-immutable-ruby failed to build in that configuration with the error.

Failure/Error: expect(sorted_set.to_a).to eq([7,1,2,10]) expected: [7, 1, 2, 10] got: [7, 8, 2, 10]

This has been confirmed locally with a more recent snapshot.

See https://launchpad.net/ubuntu/+archive/test-rebuild-20231215-noble-glibc/+build/27536849/+files/buildlog_ubuntu-noble-amd64.ruby-immutable-ruby_0.1.0-2_BUILDING.txt.gz for full logs, https://people.canonical.com/~ginggs/ftbfs-report/test-rebuild-20231215-noble-glibc-noble.html for the glibc rebuild report, and https://launchpad.net/~ubuntu-toolchain-r/+archive/ubuntu/glibc for the most recent glibc snapshot.