RFR: Grand heuristics and tests rehash

[Aleksey Shipilev]

On 09/06/2018 09:37 PM, Aleksey Shipilev wrote:
> Therefore, I vote for removing all partial heuristics and the associated matrix code. Removing that
> code simplifies our development, testing, and backporting significantly. There is even less need to
> drag this thing upstream. If we ever need matrix stuff back, we can revert it from the Mercurial
> history.

My dirty removal patch recovers >2 KLOC:
   49 files changed, 85 insertions(+), 2097 deletions(-)

It would probably remove more once I search for unused methods.

-Aleksey