RFR(S): 8221342: [TESTBUG] Generate Dockerfile for docker testing

[Jie Fu]

> Hi Jie,
>
> On 25/03/2019 12:20 pm, Jie Fu wrote:
>> Hi David,
>>
>> No, I didn't specify the custom image name and version.
>> I had just assumed that it can be dynamically and automatically 
>> generated  based on my test environment.
>
> How did you envisage that working?
I just hope so.
But Misha's change is good enough to me.


>
>> So I think it might be better to update the jdk/doc/testing.md for 
>> the docker tests.
>
> Yes the docs will also need updating, with instructions on running 
> tests via make and directly via jtreg.
Thanks.

Best regards,
Jie