Clean up test for registry used by Package.build() by default (#1704)
Clean up test for registry used by Package.build() by default (#1704)

PackageTest.test_default_registry() was exactly the same as
PackageTest.test_build() since 32f384c59f562061d0f506f3d5c3647420e1054f.
quiltdata/quilt-compiler,quiltdata/quilt,quiltdata/quilt,quiltdata/quilt-compiler,quiltdata/quilt,quiltdata/quilt,quiltdata/quilt-compiler,quiltdata/quilt-compiler,quiltdata/quilt