JDK 8 code review request for 6838776 Defer initialization of static fields in java.math.BigInteger

[joe . darcy]

Hello.

Please review this change to only instantiated an Unsafe object in 
BigInteger and BigDecimal if serialization is done:

   6838776 Defer initialization of static fields in java.math.BigInteger
   http://cr.openjdk.java.net/~darcy/6838776.0/

Thanks,

-Joe