The dump function was the only part of this class which depended on
high-level functionality. This was due to the DumpDataExtractor
function, which uses info from a running target to control dump format
(although, RegisterValue doesn't really use the high-level part of
This patch follows the same approach done for the DataExtractor class,
and extracts the dumping code into a separate function/file. This file
can stay in the higher level code, while the RegisterValue class and
anything that does not depend in dumping can stay go to lower layers.