go/types, types2: establish type-checker specific local tests

Establish testdata/local directory for tests that are not (yet)
shared between the go/types and types2. Move issue47996.go into
that directory.

For #54511.

Change-Id: I274b119990a93cc3657bdddc5246948699226c21
Reviewed-on: https://go-review.googlesource.com/c/go/+/426660
Reviewed-by: Robert Findley <rfindley@google.com>
Auto-Submit: Robert Griesemer <gri@google.com>
Run-TryBot: Robert Griesemer <gri@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@google.com>

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

@@ -305,7 +305,8 @@ func TestSpec(t *testing.T)     { testDirFiles(t, "../../../../go/types/testdata
 func TestExamples(t *testing.T) { testDirFiles(t, "../../../../go/types/testdata/examples", 45, false) } // TODO(gri) narrow column tolerance
 func TestFixedbugs(t *testing.T) {
 	testDirFiles(t, "../../../../go/types/testdata/fixedbugs", 100, false)
-} // TODO(gri) narrow column tolerance
+}                            // TODO(gri) narrow column tolerance
+func TestLocal(t *testing.T) { testDirFiles(t, "testdata/local", 0, false) }
 
 func testDirFiles(t *testing.T, dir string, colDelta uint, manual bool) {
 	testenv.MustHaveGoBuild(t)

src/go/types/check_test.go

@@ -362,6 +362,7 @@ func TestCheck(t *testing.T)     { DefPredeclaredTestFuncs(); testDirFiles(t, "t
 func TestSpec(t *testing.T)      { testDirFiles(t, "testdata/spec", false) }
 func TestExamples(t *testing.T)  { testDirFiles(t, "testdata/examples", false) }
 func TestFixedbugs(t *testing.T) { testDirFiles(t, "testdata/fixedbugs", false) }
+func TestLocal(t *testing.T)     { testDirFiles(t, "testdata/local", false) }
 
 func testDirFiles(t *testing.T, dir string, manual bool) {
 	testenv.MustHaveGoBuild(t)

src/go/types/testdata/local/issue47996.go

@@ -0,0 +1,9 @@
+// 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 p
+
+// don't crash
+// TODO(gri) make this test work for go/types
+// func T[P] m() {}