Fix MergeJoinSorter.SortKey as the fasterXML may call readNext() even
after the first return of null values (indicating end of input data).
Add code to MBigDecimal#ReadCollation() which may be tripped up by the
tests.
Make sure test gets the correct queryContext.
Update the MergeJoinSert sortKey to use Persistit Value for the row, not
a Key for the row value. The conversion from row<->Value via
PersistitValuePValue{source|target} works better and has more support
for the odd values (like BigDecimal). Add a test to verify the expanded
types support works as expected.
Fix the KeyReaderWriter test based on the change of the MergeJoinSort
from Key to Value
Fix OOM in MergeJoinSort by no using a class Value, but creating a new
one for each row. Eliminates one copy of the data.
Need to copy the Value to not store a set of cache values, which doubles
the size of the initial storage, and again, causes the OOM to occur.
merge tjoneslo: Fix mergejoinsorter

Merge pull request #894 from tjoneslo/akiban-server/fix-mergejoinsorter
https://github.com/FoundationDB/sql-layer/pull/894