RFR(XS): 8219961: [ppc64] Increase code size for interpreter generation.

[Lindenmaier, Goetz]

Hi, 

please review this tiny fix for OpenJDK 8.
If an agent is specified, the VM does not start on ppc64.
The space for the template interpreter does not suffice any more.
http://cr.openjdk.java.net/~goetz/wr19/8219961-ppc64_interpreter_8/01/

Best regards,
  Goetz.