typeparams: don't complain that Go 1.17 doesn't support iterators

This fixes a test that broke when iterator methods were added
to go/types in CL 575455.

Fixes golang/go#69000

Change-Id: I2c60bbaa3a8c1f059d6d335ec40962e1215375b8
Reviewed-on: https://go-review.googlesource.com/c/exp/+/607895
Reviewed-by: Robert Findley <rfindley@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Alan Donovan <adonovan@google.com>

typeparams/typeparams_test.go

@@ -14,6 +14,7 @@ import (
 	"go/parser"
 	"go/token"
 	"go/types"
+	"strings"
 	"testing"
 )
 
@@ -35,6 +36,12 @@ func TestAPIConsistency(t *testing.T) {
 		delete(api118, name)
 	}
 	for name, api := range api118 {
+		// Go 1.23 has iterator methods that return Seq.
+		// These methods can't be supported at 1.17.
+		if strings.Contains(api, "Seq") && api117[name] == "" {
+			continue
+		}
+
 		if api != api117[name] {
 			t.Errorf("%q: got %s at 1.18+, but %s at 1.17", name, api, api117[name])
 		}