Update TestNormalize to only test Windows

The output of platforms.DefaultSpec() and the normalized version of the
default platform on 32- and 64-bit ARM are not comparable. This test
was added to validate not losing Windows-specific information during
normalize of the platform object, so for now we are moving this to be a
Windows-only test until we resolve the right behavior on ARM.

Signed-off-by: Phil Estes <estesp@amazon.com>

platforms/platforms_test.go

@@ -23,7 +23,6 @@ import (
 	"testing"
 
 	specs "github.com/opencontainers/image-spec/specs-go/v1"
-	"github.com/stretchr/testify/require"
 )
 
 func TestParseSelector(t *testing.T) {
@@ -365,7 +364,3 @@ func TestParseSelectorInvalid(t *testing.T) {
 		})
 	}
 }
-
-func TestNormalize(t *testing.T) {
-	require.Equal(t, DefaultSpec(), Normalize(DefaultSpec()))
-}