RFR: JDK-8211343: nsk_jvmti_parseoptions should handle multiple suboptions

[Gary Adams]

Here is a first pass at a replacement parser for jvmti test options.

  Webrev: http://cr.openjdk.java.net/~gadams/8211343/webrev.00/
  Issue: https://bugs.openjdk.java.net/browse/JDK-8211343

Testing is in progress. Need to check out more platforms.
On local linux testing one jvmti test failed SetNativeMethodPrefix001
which passed an empty options string.
...