go/ssa: remove outdated any normalizer setting up in test

Remove the outdated normalizer for formatting interface{} as
any during tests.

* another benefit is we remove the un-exported test function from
  example, it's clearer for pkgsite and godoc users.

go/ssa/example_test.go

@@ -60,9 +60,6 @@ func main() {
 // syntax, perhaps obtained from golang.org/x/tools/go/packages.
 // In that case, see the other examples for simpler approaches.
 func Example_buildPackage() {
-	// Replace interface{} with any for this test.
-	ssa.SetNormalizeAnyForTesting(true)
-	defer ssa.SetNormalizeAnyForTesting(false)
 	// Parse the source files.
 	fset := token.NewFileSet()
 	f, err := parser.ParseFile(fset, "hello.go", hello, parser.ParseComments)

go/ssa/print.go

@@ -39,16 +39,8 @@ func relName(v Value, i Instruction) string {
 	return v.Name()
 }
 
-// normalizeAnyForTesting controls whether we replace occurrences of
-// interface{} with any. It is only used for normalizing test output.
-var normalizeAnyForTesting bool
-
 func relType(t types.Type, from *types.Package) string {
-	s := types.TypeString(t, types.RelativeTo(from))
-	if normalizeAnyForTesting {
-		s = strings.ReplaceAll(s, "interface{}", "any")
-	}
-	return s
+	return types.TypeString(t, types.RelativeTo(from))
 }
 
 func relTerm(term *types.Term, from *types.Package) string {

go/ssa/testhelper_test.go

@@ -1,10 +0,0 @@
-// Copyright 2021 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package ssa
-
-// SetNormalizeAnyForTesting is exported here for external tests.
-func SetNormalizeAnyForTesting(normalize bool) {
-	normalizeAnyForTesting = normalize
-}