RFR 8247741: Test test/hotspot/jtreg/runtime/7162488/TestUnrecognizedVmOption.java fails when -XX:+IgnoreUnrecognizedVMOptions is set

[Harold Seigel]

Hi,

Please review this small fix (suggested by dholmes) for JDK-8247741.  
The fix avoids using createTestJvm() to prevent JTreg flags from being 
passed to the new process created by the test.

Open Webrev: 
http://cr.openjdk.java.net/~hseigel/bug_8247741/webrev/index.html

JBS Bug: https://bugs.openjdk.java.net/browse/JDK-8247741

The fix was tested by running the test using Mach5 and by running it by 
hand with -vmoptions:"-XX:+IgnoreUnrecognizedVMOptions" specified on the 
JTReg command line.

Thanks, Harold