RFR(XXS): 8130315: Fix wrong prototype of GrowKnownVMs() in java.c

[Volker Simonis]

Hi,

could someone please review this tiny fix:

http://cr.openjdk.java.net/~simonis/webrevs/2015/8130315/
https://bugs.openjdk.java.net/browse/JDK-8130315

Because of this bug jdk9 doesn't build without
'--disable-warnings-as-errors' on SLES 12 with gcc 4.8.3

Thank you and best regards,
Volker