Float checking safeguards

[quetric]

accumulate in double and increase tolerances to cover slight mismatches between kernel and host float accumulation. Fixes #225

[github-actions]

Coverage

component	covered	total		vs dev
linker	1566	3869	40.5%	no change
vrt	10895	14898	73.1%	no change
vrtd	1982	5153	38.5%	no change

_{Lines covered at f1fa2af, compared with the most recent successful dev run. Full HTML reports are attached to the test runs as artifacts.}