cmd/compile: turn off variable-sized make() stack allocation with -N

Give people a way to turn this optimization off.

(Currently the constant-sized make() stack allocation is not disabled
with -N. Kinda inconsistent, but oh well, probably worse to change it now.)

Update #73253

Change-Id: Idb9ffde444f34e70673147fd6a962368904a7a55
Reviewed-on: https://go-review.googlesource.com/c/go/+/664655
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Jorropo <jorropo.pgm@gmail.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: t hepudds <thepudds1460@gmail.com>

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

diff --git a/src/cmd/compile/internal/walk/builtin.go b/src/cmd/compile/internal/walk/builtin.go
index f5e558b..0187822 100644
--- a/src/cmd/compile/internal/walk/builtin.go
+++ b/src/cmd/compile/internal/walk/builtin.go
@@ -568,7 +568,7 @@
 			// The conv is necessary in case n.Type is named.
 			return walkExpr(typecheck.Expr(typecheck.Conv(s, n.Type())), init)
 		}
-		tryStack = true
+		tryStack = base.Flag.N == 0
 	}
 
 	// The final result is assigned to this variable.