RFR: 8240698: LingeredApp does not pass getTestJavaOpts() to the children process if vmArguments is already specified

[Leonid Mesnik]

Hi

Could you please review following fix which change LingeredApp to 
prepend vm options to java/vm.test.opts when startApp is used and 
provide startAppVmOpts to override options completely.

The intention is to avoid issue like in this bug where test/jtreg 
options were ignored by tests. Also I fixed some tests where intention 
was to append vm options rather than to override them.

webrev: http://cr.openjdk.java.net/~lmesnik/8240698/webrev.00/

bug: https://bugs.openjdk.java.net/browse/JDK-8240698

Leonid