fix double int without breaking stdin

[grosser]

reproduction:

source "https://rubygems.org"

gem "parallel_tests", path: "~/Code/tools/parallel_tests"
gem "minitest"
gem "rspec"

# a_spec.rb
sleep 5; describe { specify { 'Should not get here' }; specify { p 'Should not get here either'} }

# a_test.rb
require "minitest/autorun"

describe "foo" do
  it "do" do
    # binding.irb
    puts "foo"
    sleep 10
  end
end

trap("SIGINT")  do
  puts "GOT INT A"
  $stdout.flush
end

• run test and Ctrl+c -> 1 GOT INT
• run test and uncomment binding.irb shell works
• run spec and interrupt -> does not run tests

issues:
integration test fails ... I think this is because it's not a cgroup so the signal does not reach all tests
so I expect this to also happen on CI which could mean tests hang forever
also tried with (parallel_rspec test/a_spec.rb -n 2 &) and then kill -int but also worked

[grosser]

this seems to work for

• foreground
• background
• started via integration test
  ... so I hope that covers all cases