8222888: [TESTBUG] docker/TestJFREvents.java fails due to "RuntimeException: JAVA_MAIN_CLASS_* is not defined"

[Leonid Mesnik]

Looks good.

Leonid

> On Apr 24, 2019, at 1:03 PM, mikhailo.seledtsov at oracle.com wrote:
> 
> Please review this change that makes a test more robust. The test originally relied on the fact that JAVA_MAIN_CLASS variable
> is always present when running jtreg tests. This assumption is wrong, hence I reworked the test to define its own unique
> environment variable.
> 
> In order to introduce environment variable I reworked the DockerTestUtils a little bit, by splitting the
> dockerRunJava() method into 2: buildJavaCommand() to build the command; dockerRunJava() uses buildJavaCommand()
> then runs the command. This allowed me to introduce the test environment variable to the child process.
> The behavior of dockerRunJava() should not be affected by this change, it is a simle split.
> 
>     JBS: https://bugs.openjdk.java.net/browse/JDK-8222888
>     Webrev: http://cr.openjdk.java.net/~mseledtsov/8222888.00/
>     Testing:
>         1. Ran hotspot docker tests on Linux-x64 machine with docker enigne configured.
>            Ran both via jtreg directly and via make
>            All PASS
> 
> Thank you,
> Misha
>