Bug#888733: hyantesite: test failures on most architectures

[Rebecca N. Palmer]

Control: found -1 1.3.0-1.1
Control: retitle -1 hyantesite: test failures on most architectures

At least on i386, this *isn't* just -0 vs +0 and last-digit rounding 
errors: in test 'family' (which applies a cone smoother to a regularly 
spaced set of spikes), centre points drop from highest to 0, e.g.

-9.000000 4.990000 0.109082
-9.000000 5.000000 0.228827
-9.000000 5.010000 0.109082

+9.000000 4.990000 0.110345
+9.000000 5.000000 0.000000
+9.000000 5.010000 0.110345

It also fails in 1.3.0-1.1 if the tests are run (they aren't by 
default).  This fails even on amd64 buster, though not as badly: only a 
last-digit error (in test 'ra').