Skip skipping thread scheme (#1972)
Several simplification tests (all with the bounds [-3,1]) were run:
5+0.05 8 threads, failed very quickly:
http://tests.stockfishchess.org/tests/view/5c439a020ebc5902bb5d3970
20+0.2 8 threads, also failed, but needed a lot more games:
http://tests.stockfishchess.org/tests/view/5c44b1b70ebc5902bb5d4e34
60+0.6 8 threads passed:
http://tests.stockfishchess.org/tests/view/5c48bfe40ebc5902bca15325
60+0.6 4 threads passed:
http://tests.stockfishchess.org/tests/view/5c4b71a00ebc593af5d49904
No functional change.