RFR JDK-8197533 move javax.transaction.xa into its own module

[Paul Sandoz]

+1

> On Mar 1, 2018, at 8:59 AM, Lance Andersen <lance.andersen at oracle.com> wrote:
>> 
>> +1, i second Joe’s request to update package-info.java while we are opportunistically cleaning this area up.
> 
> Per your and Joe’s request, please see cr.openjdk.java.net/~lancea/8197533/webrev.02 <http://cr.openjdk.java.net/~lancea/8197533/webrev.02> which has your suggested update to use package-info.java
> 
> Thank you both
> 
> Best
> Lance