Ruby

.travis.yml: Update to use arm64/ppc64le/s390x.

• Use only the free pipelines arm64/ppc64le/s390x without credits on Travis.
  See https://docs.travis-ci.com/user/billing-overview/#partner-queue-solution.
• Add ppc64le case.
• Update the gcc to gcc-11.
• Remove unused logic.
• Add the tool/travis_wait.sh to avoid a command timeout.
• Run the tests skipping some failing tests.
  • Set TEST_ALL_SKIPPED_TESTS env to skip the tests.
  • Run the tests separately returning ok status.
    The tests are executed if TEST_ALL_SKIPPED_TESTS env is set or
    TEST_ALL_SEPARATED_TESTS env is set.
  • Add tool/ci_functions.sh to manage the functions used in CI.
• Add arm64 to allow_failures due to the following issue.
  An arm64 job sometimes does not start right now.
  https://travis-ci.community/t/11629