Introduce concurrent on-stack replacement.

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index 2183fb434a9d24400ec9814a941daa0d120de2db..b289877a6fe63384a9744ff4b49a653080f03b66 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -10785,7 +10785,8 @@ void Code::Disassemble(const char* name, FILE* out) {
     // If there is no back edge table, the "table start" will be at or after
     // (due to alignment) the end of the instruction stream.
     if (static_cast<int>(offset) < instruction_size()) {
-      FullCodeGenerator::BackEdgeTableIterator back_edges(this);
+      DisallowHeapAllocation no_gc;
+      FullCodeGenerator::BackEdgeTableIterator back_edges(this, &no_gc);
 
       PrintF(out, "Back edges (size = %u)\n", back_edges.table_length());
       PrintF(out, "ast_id  pc_offset  loop_depth\n");