RFR(XS): 8153835: Fix range of flag MaxDirectMemorySize which is parsed at jlong.

[Lindenmaier, Goetz]

Hi,

The upper limit of the range for flag MaxDirectMemorySize is MAX_SIZE_T.
The flag is used to set a property that is parsed into a long. Thus, the max
value on 64-bit platforms is too large.
Fix: Limit the range to max_jlong, too.

Please review this change. I please need a sponsor.
http://cr.openjdk.java.net/~goetz/wr16/8153835-MaxDMSz/webrev.01/

Best regards,
  Goetz.