envutil.rb: assert_syntax_error
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@38723 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
envutil.rb: assert_syntax_error
new assertion for syntax error and error message.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@38723 b2dd03c8-39d4-4d8f-98ff-823fe69b080e