GDBJIT: do not register NULL lineinfo when gdbjit integration is disabled.

src/full-codegen.cc

Index: src/full-codegen.cc
diff --git a/src/full-codegen.cc b/src/full-codegen.cc
index 9366e427a15598888cff7b1f4609e3527f1c9c83..af3ac00bae991ea2b18b33f1638214a03a2e9aa1 100644
--- a/src/full-codegen.cc
+++ b/src/full-codegen.cc
@@ -308,7 +308,7 @@ bool FullCodeGenerator::MakeCode(CompilationInfo* info) {
   CodeGenerator::PrintCode(code, info);
   info->SetCode(code);  // may be an empty handle.
 #ifdef ENABLE_GDB_JIT_INTERFACE
-  if (!code.is_null()) {
+  if (FLAG_gdbjit && !code.is_null()) {
     GDBJITLineInfo* lineinfo =
         masm.positions_recorder()->DetachGDBJITLineInfo();