Rework the Destination filesystem to make --renderStaticToDisk work

See #9626

publisher/htmlElementsCollector_test.go

@@ -23,7 +23,6 @@ import (
 	"time"
 
 	"github.com/gohugoio/hugo/config"
-
 	"github.com/gohugoio/hugo/media"
 	"github.com/gohugoio/hugo/minifiers"
 	"github.com/gohugoio/hugo/output"
@@ -139,7 +138,7 @@ func TestClassCollector(t *testing.T) {
 					if skipMinifyTest[test.name] {
 						c.Skip("skip minify test")
 					}
-					v := config.New()
+					v := config.NewWithTestDefaults()
 					m, _ := minifiers.New(media.DefaultTypes, output.DefaultFormats, v)
 					m.Minify(media.HTMLType, w, strings.NewReader(test.html))