JDK 12 RFR of JDK-8219254: Update explicit uses of latest source/target in langtools tests to a property

[Joe Darcy]

Hi Jon,

As a general note, it occurred to me that when the current release 
number is referred to inside the source of a test, rather than passing 
it through the command line, it can instead be gotten programmatically 
using code like:

     Integer.toString(Runtime.version().feature())

The start of JDK 12 updates included changes like this for the libraries 
tests.

If you agree this is preferable, I can revise the webrev to use this 
technique where appropriate in the langtools tests.

Thanks,

-Joe

On 2/19/2019 10:40 AM, Jonathan Gibbons wrote:
>
>
> On 02/19/2019 10:23 AM, Joe Darcy wrote:
>>
>> Besides the future work files under diags/examples, after the changes 
>> in the webrev, the remaining uses of "-source 13" are in
>>
>>     ./tools/javac/expswitch/ExpSwitchNestingTest.java
>
> Because this is a singleton file, it might be easiest to convert it to 
> a "normal" jtreg test -- still using TestNG of course -- by removing 
> the TEST.properties file, and using the standard test description 
> tags, ending with `@run testng ...` to run the test.
>
> -- Jon