RFR: JDK-8235252: Repair run_tests.sh by locating jtreg locally

[Alexander Matveev]

http://cr.openjdk.java.net/~almatvee/8235252/webrev.01/
- Updated script to use JT_HOME first if set, then use JT_BUNDLE_URL if set.
- Also, renamed JTREG_ to JT_ in variables names to align with rest of JDK.

Not sure why we did not use jtreg used by all the other tests. 
run_tests.sh used for convenience to generate and verify packages 
generated by jpackage. This process done in 5 stages: generating 
packages (jtreg test), installation (requires user input), verify 
installation, uninstall (requires user input) and verify uninstall. This 
is why we using helper script to simplify this process.

Thanks,
Alexander

On 12/10/2019 3:32 PM, Alexey Semenyuk wrote:
> http://cr.openjdk.java.net/~almatvee/8235252/webrev.01/ looks good.
>
> - Alexey
>
> On 12/10/2019 4:49 PM, Jonathan Gibbons wrote:
>> This seems ... surprising.
>>
>> Why is the instance of jtreg used for all the other tests not good 
>> enough here?
>>
>> -- Jon
>>
>> On 12/10/19 1:35 PM, Alexander Matveev wrote:
>>> Please review simple script fix [2] for jpackage bug [1].
>>>
>>>  - Modified script to download jtreg bundle from URL provided by 
>>> environment variable JTREG_BUNDLE_URL.
>>>
>>> Thanks,
>>> Alexander
>>>
>>> [1] https://bugs.openjdk.java.net/browse/JDK-8235252
>>>
>>> [2] http://cr.openjdk.java.net/~almatvee/8235252/webrev.00/
>