Revert "Shuffle detection #2064"

It causes a serious regression hanging a simple fixed
depth search. Reproducible with:

position fen q1B5/1P1q4/8/8/8/6R1/8/1K1k4 w - - 0 1
go depth 13

The reason is a search tree explosion due to:

if (... && depth < 3 * ONE_PLY)
      extension = ONE_PLY;

This is very dangerous code by itself because triggers **at the leafs**
and in the above position keeps extending endlessly. In normal games
time deadline makes the search to stop sooner or later, but in fixed
seacrch we just hang possibly for a very long time. This is not acceptable
because 'go depth 13' shall not be a surprise for any position.

This patch reverts commit 76f1807baa90eb69f66001d25df2a28533f9406f.
and fixes the issue https://github.com/official-stockfish/Stockfish/issues/2091

Bench: 3243738