assert_syntax_error returns the exception [ci skip]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58458 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/lib/test/unit/assertions.rb

@@ -513,6 +513,7 @@ EOT
             RubyVM::InstructionSequence.compile(src, fname, fname, line)
           end
           assert_match(error, e.message, mesg)
+          e
         end
       end