Fix %w verb in t.Errorf calls

[peterstace]

Description

This is to fix the following test build error:

$ go test ./geom
# github.com/peterstace/simplefeatures/geom_test
geom/alg_set_op_test.go:990:7: (*testing.common).Errorf does not support error-wrapping directive %w
geom/ctor_options_test.go:41:5: (*testing.common).Errorf does not support error-wrapping directive %w
FAIL    github.com/peterstace/simplefeatures/geom [build failed]
FAIL

Note that this error only seems to occur with go1.18. I'm not really sure why this is coming up as an actual compile error rather than a vet warning (I haven't looked into it).

Check List

Have you:

• Added unit tests? N/A

• Add cmprefimpl tests? (if appropriate?) N/A

• Updated release notes? (if appropriate?) N/A

Related Issue

• N/A

Benchmark Results

N/A