RFR [XS]: 8235489: handle return values of sscanf calls in hotspot

[Baesken, Matthias]

Hello,  I noticed there are some remaining sscanf calls  in the hotspot codebase missing return value checks.
Those should better be checked  .


Bug/webrev :

https://bugs.openjdk.java.net/browse/JDK-8235489

http://cr.openjdk.java.net/~mbaesken/webrevs/8235489.0/


Thanks, Matthias