cmd/compile: spurious inference error with undefined value

```
% cat /tmp/x.go
package p

import "slices"

var s struct{ x int }

func _() {
	slices.Clip(s.y)
}
% go build /tmp/x.go
# command-line-arguments
/tmp/x.go:8:13: cannot infer S ($GOROOT/src/slices/slices.go:403:11)
/tmp/x.go:8:16: s.y undefined (type struct{x int} has no field or method y)
% 
```

The first error should not be printed, since it is caused by the second error.