Disable kDebugStackWalk

Someone left it enabled.

Bug: 27039049

Change-Id: I2bec610a3f20e1214dc34b4e06227609da2a2ab8
diff --git a/runtime/stack.cc b/runtime/stack.cc
index 1e82860..5faff93 100644
--- a/runtime/stack.cc
+++ b/runtime/stack.cc
@@ -40,7 +40,7 @@
 
 namespace art {
 
-static constexpr bool kDebugStackWalk = true;
+static constexpr bool kDebugStackWalk = false;
 
 mirror::Object* ShadowFrame::GetThisObject() const {
   ArtMethod* m = GetMethod();