Fix floating point precision failure caused by FMA on ppc64le
Fix floating point precision failure caused by FMA on ppc64le

This was exposed while testing CockroachDB.
The geomfn/TestShortestLineString fails due to floating point precision differences caused by FMA on ppc64le.
See https://go.dev/ref/spec#Floating_point_operators for more details.

twpayne/go-geom