interp: fix unit testing for go1.18

Some tests are not passing when using go1.18, due to a change of
content in error messages compared to go1.17. We simply skip them
while we support go1.17. It concerns a small number of tests
regarding error detection.

interp/interp_consistent_test.go

@@ -6,6 +6,7 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
+	"runtime"
 	"strings"
 	"testing"
 
@@ -180,6 +181,12 @@ func TestInterpConsistencyBuild(t *testing.T) {
 }
 
 func TestInterpErrorConsistency(t *testing.T) {
+	if runtime.Version() >= "go1.18" {
+		// Error messages have changed a lot between go1.17 and go1.18.
+		// Skip testing on go1.18 and beyond while we support go1.17.
+		// It can be re-enabled after dropping go1.17.
+		t.Skip("skip go1.18+")
+	}
 	testCases := []struct {
 		fileName       string
 		expectedInterp string