Regression test for 'references' bug golang/go#60369: a references
query on the embedded type name T in struct{p.T} instead reports all
references to the package name p.

The bug was fixed in release go1.21 of go/types.

-- flags --
-min_go=go1.21

-- go.mod --
module example.com
go 1.12

-- a/a.go --
package a

type A struct{}
const C = 0

-- b/b.go --
package b

import a "example.com/a" //@loc(adef, "a")
type s struct { a.A } //@loc(Aref1, "A"), loc(aref1, "a"), refs(Aref1, Aref1, Aref3), refs(aref1, adef, aref1, aref2, aref3)
var _ a.A //@loc(aref2, re" (a)"), loc(Aref2, "A")
var _ = s{}.A //@loc(Aref3, "A")
const c = a.C //@loc(aref3, "a")