merge revision(s) c1d78a7f0ece2004822193a0c1f1fd3dc38c2fdf: [Backport #15360]
do_mutex_lock: release mutex before checking for interrupts (fixes issue 15360)
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_5@67764 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
merge revision(s) c1d78a7f0ece2004822193a0c1f1fd3dc38c2fdf: [Backport #15360]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_5@67764 b2dd03c8-39d4-4d8f-98ff-823fe69b080e