Dynamic formats performance regressions

Some dynamic formats have a worse than 10% performance regression since 1.8.0-jumbo-1. Comparing with --disable-openmp for both versions and also Benchmarks_1_8 = Y for the current bleeding-jumbo:

Ratio:  0.73261 real, 0.73992 virtual   dynamic_15:Many salts
Ratio:  0.82377 real, 0.82377 virtual   dynamic_16:Many salts
Ratio:  0.76493 real, 0.76493 virtual   dynamic_24:Many salts
Ratio:  0.76474 real, 0.76474 virtual   dynamic_25:Many salts
Ratio:  0.71870 real, 0.71870 virtual   dynamic_35:Many salts
Ratio:  0.72531 real, 0.72531 virtual   dynamic_36:Many salts
Ratio:  0.76323 real, 0.76323 virtual   dynamic_37:Many salts
Ratio:  0.81191 real, 0.81191 virtual   dynamic_40:Many salts
Ratio:  0.83398 real, 0.83398 virtual   dynamic_61:Many salts
Ratio:  0.80492 real, 0.79694 virtual   dynamic_1016:Many salts
Ratio:  0.76038 real, 0.76038 virtual   dynamic_1401:Many salts
Ratio:  0.87405 real, 0.86527 virtual   dynamic_1401:Only one salt
Ratio:  0.87461 real, 0.87461 virtual   dynamic_1501:Only one salt
Ratio:  0.75675 real, 0.75675 virtual   dynamic_1504:Many salts
Ratio:  0.84177 real, 0.84177 virtual   dynamic_2001:Many salts
Ratio:  0.79714 real, 0.79714 virtual   dynamic_2004:Many salts
Ratio:  0.72865 real, 0.72865 virtual   dynamic_2005:Many salts
Ratio:  0.87991 real, 0.87991 virtual   dynamic_2006:Many salts
Ratio:  0.83394 real, 0.82568 virtual   dynamic_2008:Many salts
Ratio:  0.79867 real, 0.79867 virtual   dynamic_2009:Many salts
Ratio:  0.82579 real, 0.82579 virtual   dynamic_2010:Many salts
Ratio:  0.82581 real, 0.82581 virtual   dynamic_2011:Many salts
Ratio:  0.73347 real, 0.73347 virtual   dynamic_2014:Many salts