.cirrus.yml: Add Cirrus CI for Arm64 tests.

[junaruga]

This PR is based on #4772 to enable Cirrus CI to test Arm cases. Initially there are 2 cases, the latest clang 12 and gcc 11 available on our CI image: http://ghcr.io/ruby/ruby-ci-image .

I would like to use the Cirrus Ci to cover some cases on Arm. We can add maximum 16 cases. The entire testing design is inspired from .github/workflows/compilers.yml .

Note

• As I found an issue in rubygems tests with the environment variable make, I am using make_cmd for now, You can see rubygems tests failing with customized environment variable "make" rubygems/rubygems#4921 for detail.
• I added the badge image to the README. The updated README is here.
• This CI is also executed at the timing of push on forked repo like other CIs. It's good to test on your forked repo without sending PR.
• The tool/disable_ipv6.sh is what we used in ruby/ruby in the past. We reused the script again.

[junaruga]

The total running time is

• clang-12: 05:01
• gcc-11: 03:34
  https://cirrus-ci.com/build/4848426694213632

So, it finishes faster than other CIs. That's good to add this CI.

My concern is the following part in make test-all. Some tests are retried. I don't know why the tests are retried while other CI results, such as the logs by .github/workflows/ubuntu.yml and .travis.yml don't print this kind of message.

https://cirrus-ci.com/task/5219912575614976

$make_cmd test-all
config.status: creating ruby-runner.h
making mjit_build_dir.so
Run options: 
  --seed=27671
  "--ruby=./miniruby -I./lib -I. -I.ext/common  ./tool/runruby.rb --extout=.ext  -- --disable-gems"
  --excludes-dir=./test/excludes
  --name=!/memory_leak/
  -q
  --color=always
  --tty=no
# Running tests:

Retrying...
[  1/127] TestDefined#test_autoloaded_noload = 0.00 s
[  2/127] TestDefined#test_autoloaded_subclass = 0.00 s
...
[126/127] TestKeywordArguments#test_zsuper_only_anonymous_kwrest = 0.00 s
[127/127] TestKeywordArguments#test_zsuper_only_named_kwrest = 0.00 s
Finished tests in 84.888216s, 247.7493 tests/s, 31488.2456 assertions/s.
21031 tests, 2672981 assertions, 0 failures, 0 errors, 190 skips
ruby -v: ruby 3.1.0dev (2021-09-20) [aarch64-linux]

[junaruga]

@shyouhei is it possible to review this PR, as it includes the new file .cirrus.yml? Thanks.

[junaruga]

Rebased with using GNUMAkEFLAGS.

echo "GNUMAKEFLAGS=$GNUMAKEFLAGS"
GNUMAKEFLAGS=-s -j9

The total running time that I tested on my forked repo is
https://cirrus-ci.com/build/4609835590221824

• clang-12: 05:01
• gcc-11: 03:34
  It's exactly same time with previous one.

This PR's running time is like this. Maybe the start was queued and delayed.
https://cirrus-ci.com/build/5755328030572544

• clang-12: 06:04
• gcc-11: 04:08

As a reference, I also tested the total running time without concurrent jobs -jN by executing the make without setting the GNUMAKEFLAGS. The running time is much longer as expected.
https://cirrus-ci.com/build/5528881986797568

• clang-12: 23:30
• gcc-11: 16:49

[junaruga]

Note the 1 failing by the failed JIT tests on Visual Studio 20219 on Windows is what randomly happens according to kokubun's research yesterday. https://github.com/ruby/ruby/pull/4875/checks?check_run_id=3664926540 . It's not related to this PR.

[shyouhei]

Great!

[shyouhei]

We might also want to fix .github/workflows/compilers.yml's use of $make variable in a separate pull request.

[junaruga]

@shyouhei Thanks for the review! For the .github/workflows/compilers.yml to fix the $make, I sent the PR #4880 now.