RFR(T): 8244622: Remove SA's memory/FreeChunk.java. It's no longer used.

[Chris Plummer]

Hello,

Please review the following trivial change to remove FreeChunk.java:

https://bugs.openjdk.java.net/browse/JDK-8244622
http://cr.openjdk.java.net/~cjplummer/8244622/webrev.00/index.html

Tested with tier1 and also running all SA tests.

thanks,

Chris