Bug 1079657 - DMD: Remove the "stress" mode. r=erahm.

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extra : rebase_source : d0b233a62c1b50facb27d781f9942628f100180e
Bug 1077272 - Allow argument groups in mach commands. r=gps.

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extra : rebase_source : 478b305eedac6d30af748d80da408042aba48c14
Bug 1074656 - Merge |mach debug| and |mach dmd| into |mach run|. r=gps.

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extra : rebase_source : a9da86cadae7fdbb0fe9e3931fb1163f4239527c