go/types, types2: fix Hilbert test for stand-alone run

When run as a stand-alone test (without other tests running before),
the builtin function 'assert' (only available for testing) is missing.
Make sure it's declared.

This change only affects this test, when run stand-alone, as in:

go test -run Hilbert

Fixes #60774.

Change-Id: Ib07d97ba2670b839e8ad11ef50d0e6581bb3d79d
Reviewed-on: https://go-review.googlesource.com/c/go/+/502996
Auto-Submit: Robert Griesemer <gri@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Robert Griesemer <gri@google.com>
Reviewed-by: Robert Findley <rfindley@google.com>
Reviewed-by: Robert Griesemer <gri@google.com>

src/cmd/compile/internal/types2/hilbert_test.go

@@ -10,6 +10,8 @@ import (
 	"fmt"
 	"os"
 	"testing"
+
+	. "cmd/compile/internal/types2"
 )
 
 var (
@@ -25,6 +27,7 @@ func TestHilbert(t *testing.T) {
 		return
 	}
 
+	DefPredeclaredTestFuncs() // declare assert (used by code generated by verify)
 	mustTypecheck(string(src), nil, nil)
 }
 

src/go/types/generate_test.go

@@ -102,7 +102,7 @@ var filemap = map[string]action{
 	"context.go":      nil,
 	"context_test.go": nil,
 	"gccgosizes.go":   nil,
-	"hilbert_test.go": nil,
+	"hilbert_test.go": func(f *ast.File) { renameImportPath(f, `"cmd/compile/internal/types2"`, `"go/types"`) },
 	"infer.go": func(f *ast.File) {
 		fixTokenPos(f)
 		fixInferSig(f)

src/go/types/hilbert_test.go

@@ -12,6 +12,8 @@ import (
 	"fmt"
 	"os"
 	"testing"
+
+	. "go/types"
 )
 
 var (
@@ -27,6 +29,7 @@ func TestHilbert(t *testing.T) {
 		return
 	}
 
+	DefPredeclaredTestFuncs() // declare assert (used by code generated by verify)
 	mustTypecheck(string(src), nil, nil)
 }