Holding space for memory benchmarking issues

[pp-mo]

Since #5960, #5959 , #5950 and especially #5948 We are likely to get a few change warnings from memory benchmarks.

Doubtless some sensitivity changes may be needed, perhaps we'll have to turn off most of the memory benchmarking again. But possibly also, it will need to "settle down" after recent changes ? I think we should just routinely close these for a while, and later review as a set.

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