replace decrementing loop with -=
replace decrementing loop with -=

This could save a million iterations ...

Change-Id: I44fb228b951580bbeb5df5f6ec7be933077776ff

JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core