Review request for JDK-8013794 - JDK-8006220 caused an octane performance regression.

[Jim Laskey (Oracle)]

http://cr.openjdk.java.net/~jlaskey/8013794/webrev.00/index.html

The most significant change with PropertyMaps was the removal of embedded, replaced with extra padding fields. I added a computation for the amount of padding to be equal to round up to multiple of 4 plus 4.  This would make some structures larger than before  (the plan is to make padding related to the number of this.xxx sets in a constructor.)  This fix reverts padding to a fixed 4 extra fields (as was embedded.)