dump/restore tests failing in "legacy" with "unknown flag: ..."

see here for example:
https://mci.10gen.com/task/mongo_tools_windows_32_25534be3a725bfd9732664cdefa08956d433df5e_14_10_30_22_20_10_legacy_windows_32

I think it's something to do with the chnages to jstests that affects how command line arguments are passed to tools.