RFR: 8147456 Parsing of argument for -agentpath can write outside of allocated memory

[Sharath Ballal]

Hi,

Pls review the fix for the following bug.
 
Bug: https://bugs.openjdk.java.net/browse/JDK-8147456   
Webrev: http://cr.openjdk.java.net/~jbachorik/sponsorship/8147456/webrev.03/ 

-Sharath Ballal