changed: sparse backends default to post-processing #1744

Job	Run time
Julia lts - ubuntu-latest - x64 - pull_request	42m 40s
Julia 1 - ubuntu-latest - x64 - pull_request	1h 28m 43s
Julia pre - ubuntu-latest - x64 - pull_request	1h 29m 0s
	3h 40m 23s

Provide feedback