Switch to old stackwalker until Windows crashes are fixed

runtime/vm/profiler.cc

Index: runtime/vm/profiler.cc
diff --git a/runtime/vm/profiler.cc b/runtime/vm/profiler.cc
index f85a5c24653fbb29fe1966d79b8104a06bd544e9..dddfe5a3cff03a7b45bb76f62af426446129f5d1 100644
--- a/runtime/vm/profiler.cc
+++ b/runtime/vm/profiler.cc
@@ -36,7 +36,7 @@ DEFINE_FLAG(int, profile_depth, 8,
             "Maximum number stack frames walked. Minimum 1. Maximum 255.");
 DEFINE_FLAG(bool, profile_verify_stack_walk, false,
             "Verify instruction addresses while walking the stack.");
-DEFINE_FLAG(bool, profile_vm, false,
+DEFINE_FLAG(bool, profile_vm, true,
             "Always collect native stack traces.");
 
 bool Profiler::initialized_ = false;