cmd/compile: escape "go" wrapper closure everywhere

For go statement, the wrapper closure needs to esacpe because it
runs asynchronously. Currently, it is not allowed for closures to
escape in the runtime. We have worked around this in the runtime,
so it doesn't "go" any function with arguments and so doesn't
need wrapping. If it ever does, it is not that we can have the
closure not escape, which may lead to miscompilation. Instead,
make the closure escape (which will fail the compilation). In the
future we may allow go'd closure to escape in the runtime.

Change-Id: I5bbe47b524371d2270c242f6c275013cd52abfc1
Reviewed-on: https://go-review.googlesource.com/c/go/+/312889
Trust: Cherry Zhang <[email protected]>
Reviewed-by: Than McIntosh <[email protected]>

src/cmd/compile/internal/walk/order.go

@@ -1582,10 +1582,8 @@ func (o *orderState) wrapGoDefer(n *ir.GoDeferStmt) {
 	// (needs heap allocation).
 	cloEscapes := func() bool {
 		if n.Op() == ir.OGO {
-			// For "go", assume that all closures escape (with an
-			// exception for the runtime, which doesn't permit
-			// heap-allocated closures).
-			return base.Ctxt.Pkgpath != "runtime"
+			// For "go", assume that all closures escape.
+			return true
 		}
 		// For defer, just use whatever result escape analysis
 		// has determined for the defer.