cmd/compile: restrict //go:notinheap to runtime/internal/sys

So it won't be visible outside of runtime package. There are changes to
make tests happy:

 - For test/directive*.go files, using "go:noinline" for testing misplaced
 directives instead.
 - Restrict test/fixedbugs/bug515.go for gccgo only.
 - For test/notinheap{2,3}.go, using runtime/cgo.Incomplete for marking
 the type as not-in-heap. Though it's somewhat clumsy, it's the easiest
 way to keep the test errors for not-in-heap types until we can cleanup
 further.
 - test/typeparam/mdempsky/11.go is about defined type in user code marked
 as go:notinheap, which can't happen after this CL, though.

Fixes #46731

Change-Id: I869f5b2230c8a2a363feeec042e7723bbc416e8e
Reviewed-on: https://go-review.googlesource.com/c/go/+/421882
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Joedian Reid <joedian@golang.org>
Reviewed-by: David Chase <drchase@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

1 files changed, 0 insertions, 16 deletions

diff --git a/test/typeparam/mdempsky/11.go b/test/typeparam/mdempsky/11.go
deleted file mode 100644
index e86c038a10..0000000000
--- a/test/typeparam/mdempsky/11.go
+++ /dev/null
@@ -1,16 +0,0 @@
-// errorcheck
-
-// 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.
-
-// Reported by Cuong Manh Le.
-
-package p
-
-type a struct{}
-
-//go:notinheap
-type b a
-
-var _ = (*b)(new(a)) // ERROR "cannot convert"