Remove nil pointer check and extra NormalizePath

Signed-off-by: Gabriel Adrian Samfira <gsamfira@cloudbasesolutions.com>

Author: gabriel-samfira

frontend/dockerfile/dockerfile2llb/convert.go

@@ -995,11 +995,7 @@ func dispatchRun(d *dispatchState, c *instructions.RunCommand, proxy *llb.ProxyE
 }
 
 func dispatchWorkdir(d *dispatchState, c *instructions.WorkdirCommand, commit bool, opt *dispatchOpt) error {
-	platformOS := runtime.GOOS
-	if d.platform != nil {
-		platformOS = d.platform.OS
-	}
-	wd, err := system.NormalizeWorkdir(d.image.Config.WorkingDir, c.Path, platformOS)
+	wd, err := system.NormalizeWorkdir(d.image.Config.WorkingDir, c.Path, d.platform.OS)
 	if err != nil {
 		return errors.Wrap(err, "normalizing workdir")
 	}

solver/llbsolver/file/backend.go

@@ -68,11 +68,7 @@ func mapUserToChowner(user *copy.User, idmap *idtools.IdentityMapping) (copy.Cho
 }
 
 func mkdir(ctx context.Context, d string, action pb.FileActionMkDir, user *copy.User, idmap *idtools.IdentityMapping) error {
-	actionPath, err := system.NormalizePath("/", action.Path, runtime.GOOS, false)
-	if err != nil {
-		return errors.Wrap(err, "removing drive letter")
-	}
-	p, err := fs.RootPath(d, filepath.FromSlash(actionPath))
+	p, err := fs.RootPath(d, action.Path)
 	if err != nil {
 		return err
 	}