RFR(XS): 8042885: java does not take hexadecimal number as vm option

[Yumin Qi]

Hi, please review the small change for

bug: https://bugs.openjdk.java.net/browse/JDK-8042885
webrev: http://cr.openjdk.java.net/~minqi/8042885/

Summary: Java does not take number with hexadecimal format as options, 
like -XX:SharedBaseAddress=0x1D000000 will cause VM exit with improper 
argument. For addresses, we more like to use hexadecimal format since it 
is close to machine address display naturally.

Tests: JPRT and manual test:  java -XX:UnlockDiagnosticVMOptions 
-XX:SharedBaseAddress=0x1D000000 -Xshare:dump

Thanks
Yumin