envutil.rb: crash report on Mac OS X

* test/ruby/envutil.rb (EnvUtil.diagnostic_reports): find crash report
  on Mac OS X.

* test/ruby/envutil.rb (Test::Unit::Assertions::FailDesc): include
  crash report on Mac OS X.

* test/ruby/envutil.rb (Test::Unit::Assertions#assert_in_out_err):
  remove crash reports if exist.

* test/ruby/test_process.rb (TestProcess#test_status_kill): ditto.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@43691 b2dd03c8-39d4-4d8f-98ff-823fe69b080e