RFR 8166642: serviceability/dcmd/framework/* timeout

[Daniil Titov]

Please review the changes that fix intermittent timeout failure of serviceability/dcmd/framework/* tests.

The problem here is that these tests invoke jcmd in different ways and one of such ways is when a main class is passed to the jcmd as a VM identifier. The main class for jtreg test is com.sun.javatest.regtest.agent.MainWrapper and in some cases more than one test are running in parallel and there are multiple Java processes with com.sun.javatest.regtest.agent.MainWrapper as a main class . When it happens jcmd iterates over all Java processes that match the condition (the main class equals to com.sun.javatest.regtest.agent.MainWrapper) and executes the command for each of them. That results in the jcmd invokes the given command multiple times and attaches to Java processes not related to the current test.

The fix makes serviceability/dcmd/framework/* tests non-concurrent to ensure that they don't interact with other tests.

Bug: https://bugs.openjdk.java.net/browse/JDK-8166642 
Webrev: http://cr.openjdk.java.net/~dtitov/8166642/webrev.01

The tests ran successfully with Mach5.

Best regards,
Daniil