[compiler] Put shared function marking behind a flag

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index 9e8b06c6fc467e8ca7668d039df96b29a9f9c4eb..00f393053e1aa80a769fef2f5943764d4a79211d 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -12211,9 +12211,11 @@ void JSFunction::MarkForOptimization() {
 
 
 void JSFunction::AttemptConcurrentOptimization() {
-  // Mark the shared function for optimization regardless of whether the
-  // optimization is concurrent or not.
-  shared()->set_was_marked_for_optimization(true);
+  if (FLAG_mark_shared_functions) {
+    // Mark the shared function for optimization regardless of whether the
+    // optimization is concurrent or not.
+    shared()->set_was_marked_for_optimization(true);
+  }
 
   Isolate* isolate = GetIsolate();
   if (!isolate->concurrent_recompilation_enabled() ||