fix: check network mode when choosing resolv.conf

Host networking can use the host's resolv.conf as-is.

executor/oci/resolvconf.go

@@ -44,7 +44,7 @@ func GetResolvConf(ctx context.Context, stateDir string, idmap *idtools.Identity
 				generate = true
 			}
 			if !generate {
-				fiMain, err := os.Stat(resolvconfPath())
+				fiMain, err := os.Stat(resolvconfPath(netMode))
 				if err != nil {
 					if !errors.Is(err, os.ErrNotExist) {
 						return struct{}{}, err
@@ -63,7 +63,7 @@ func GetResolvConf(ctx context.Context, stateDir string, idmap *idtools.Identity
 			return struct{}{}, nil
 		}
 
-		dt, err := os.ReadFile(resolvconfPath())
+		dt, err := os.ReadFile(resolvconfPath(netMode))
 		if err != nil && !errors.Is(err, os.ErrNotExist) {
 			return struct{}{}, err
 		}

executor/oci/resolvconf_test.go

@@ -111,7 +111,7 @@ func TestResolvConf(t *testing.T) {
 			t.Cleanup(func() {
 				resolvconfPath = oldResolvconfPath
 			})
-			resolvconfPath = func() string {
+			resolvconfPath = func(netMode pb.NetMode) string {
 				if tt.dt == nil {
 					return "no-such-file"
 				}