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

src/codegen.cc

Index: src/codegen.cc
diff --git a/src/codegen.cc b/src/codegen.cc
index c7e6f1c83f4a18533d915d3ae99ca59f72eaea35..f9a2453a09559b7ec5a2c2c32840606ae48718c8 100644
--- a/src/codegen.cc
+++ b/src/codegen.cc
@@ -267,7 +267,7 @@ bool CodeGenerator::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();