runtime: fix stackDebug comment

Change-Id: Ia9191bd7ecdf7bd5ee7d69ae23aa71760f379aa8
Reviewed-on: https://go-review.googlesource.com/9590Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/runtime/chan_test.go

@@ -528,7 +528,7 @@ func TestMultiConsumer(t *testing.T) {
 func TestShrinkStackDuringBlockedSend(t *testing.T) {
 	// make sure that channel operations still work when we are
 	// blocked on a channel send and we shrink the stack.
-	// NOTE: this test probably won't fail unless stack1.go:StackDebug
+	// NOTE: this test probably won't fail unless stack1.go:stackDebug
 	// is set to >= 1.
 	const n = 10
 	c := make(chan int)

src/runtime/stack1.go

@@ -7,7 +7,7 @@ package runtime
 import "unsafe"
 
 const (
-	// StackDebug == 0: no logging
+	// stackDebug == 0: no logging
 	//            == 1: logging of per-stack operations
 	//            == 2: logging of per-frame operations
 	//            == 3: logging of per-word updates