clonebundles: optional memory-requirement attribution
The new REQUIREDRAM option allows a client to skip bundles it isn't
expected to handle well, e.g. without swapping. This allows a fallback
path to be provided e.g. using zstd level 10 instead of 22.
Differential Revision: https://phab.mercurial-scm.org/D8645
To run the tests, do:
cd tests/
python run-tests.py
See https://mercurial-scm.org/wiki/WritingTests for
more information on writing tests.