Fix up foperator_abs::op1_range [PR107569]

foperator_abs::op1_range works except for the NaN handling,
from:
[frange] double [-Inf, 1.79769313486231570814527423731704356798070567525844996599e+308 (0x0.fffffffffffff8p+1024)]
lhs it computes r
[frange] double [-1.79769313486231570814527423731704356798070567525844996599e+308 (-0x0.fffffffffffff8p+1024), 1.79769313486231570814527423731704356798070567525844996599e+308
+(0x0.fffffffffffff8p+1024)] +-NAN
which is correct except for the +-NAN part.
For r before the final step it makes sure to add -NAN if there is +NAN
in the lhs range, but the final r.union_ makes it unconditional +-NAN,
because the frange ctor sets +-NAN.
So, I think we need to clear it (or have some set variant which
says not to set NAN).

This patch fixes that, but isn't enough to fix the PR, something in
the assumptions handling is still broken (and the PR has other parts).

2022-11-09  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/107569
	* range-op-float.cc (foperator_abs::op1_range): Clear NaNs
	from the negatives frange before unioning it into r.