Introduce a handle zapping setting, and enable it by default for release and debug

src/api.cc

Index: src/api.cc
diff --git a/src/api.cc b/src/api.cc
index c56bc05601e06f20607e0147b0eed429e5e28816..4d654fb1efb667f8fc08aa366f64b705538e1431 100644
--- a/src/api.cc
+++ b/src/api.cc
@@ -7979,7 +7979,7 @@ DeferredHandles::~DeferredHandles() {
   isolate_->UnlinkDeferredHandles(this);
 
   for (int i = 0; i < blocks_.length(); i++) {
-#ifdef ENABLE_EXTRA_CHECKS
+#ifdef ENABLE_HANDLE_ZAPPING
     HandleScope::ZapRange(blocks_[i], &blocks_[i][kHandleBlockSize]);
 #endif
     isolate_->handle_scope_implementer()->ReturnBlock(blocks_[i]);