I have tried running the tests on a machine with 12GB of RAM, but when I do so,
the new tests get skipped saying "not enough memory", even when I specify "-M 11G"
on the command-line. The problem seems to be the change to the precisionbigmemtest
decorator in test.support. I don't understand what the purpose of the "dryrun"
flag is, but the modified condition for skipping doesn't look right to me.

(Now that I think about it, I should be able to get the tests to run by undoing
that one part of the change. I'll get back to you about the results later today.)