RUBY_REVISION is a short sha, not the full sha like on other Rubies #7628
Description
$ ruby -ve 'puts RUBY_REVISION'
jruby 9.4.1.0-SNAPSHOT (3.1.0) 2023-01-05 006cf2b9c4 OpenJDK 64-Bit Server VM 17.0.5+8 on 17.0.5+8 +jit [x86_64-linux]
006cf2b9c4
Compared to:
ruby 3.1.3p185 (2022-11-24 revision 1a6b16756e) [x86_64-linux]
1a6b16756e0ba6b95ab71a441357ed5484e33498
truffleruby 23.0.0-dev-f9113553, like ruby 3.1.3, GraalVM CE Native [x86_64-linux]
f9113553823106072f9979b72ccaae9a7e372119
This notably causes https://github.com/actions/checkout to think it's a branch name and not a commit sha, which made https://github.com/eregon/rubyspec-stats/actions/runs/4106699958/jobs/7085256582 fail.