Fix debugger wrt concurrent recompilation flag.

src/debug.cc

Index: src/debug.cc
diff --git a/src/debug.cc b/src/debug.cc
index 35970e5ee934e9eb9ff3558d98da544cfd0ebd56..6a8df7ab9c7fcd2b197bbdbc3853520295b27c82 100644
--- a/src/debug.cc
+++ b/src/debug.cc
@@ -2056,7 +2056,7 @@ void Debug::PrepareForBreakPoints() {
   // If preparing for the first break point make sure to deoptimize all
   // functions as debugging does not work with optimized code.
   if (!has_break_points_) {
-    if (FLAG_concurrent_recompilation) {
+    if (isolate_->concurrent_recompilation_enabled()) {
       isolate_->optimizing_compiler_thread()->Flush();
     }