[heap] Tracer: Eliminate prefix for external callbacks

src/heap/heap.cc

Index: src/heap/heap.cc
diff --git a/src/heap/heap.cc b/src/heap/heap.cc
index a524af14883071213d8c645d6d7da8b31dc453e4..08fe7e742631465bc222512cbf04d0bcac2dfb16 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -1292,9 +1292,7 @@ bool Heap::PerformGarbageCollection(
     GCCallbacksScope scope(this);
     if (scope.CheckReenter()) {
       AllowHeapAllocation allow_allocation;
-      TRACE_GC(tracer(), collector == MARK_COMPACTOR
-                             ? GCTracer::Scope::MC_EXTERNAL_PROLOGUE
-                             : GCTracer::Scope::SCAVENGER_EXTERNAL_PROLOGUE);
+      TRACE_GC(tracer(), GCTracer::Scope::EXTERNAL_PROLOGUE);
       VMState<EXTERNAL> state(isolate_);
       HandleScope handle_scope(isolate_);
       CallGCPrologueCallbacks(gc_type, kNoGCCallbackFlags);
@@ -1363,9 +1361,7 @@ bool Heap::PerformGarbageCollection(
     GCCallbacksScope scope(this);
     if (scope.CheckReenter()) {
       AllowHeapAllocation allow_allocation;
-      TRACE_GC(tracer(), collector == MARK_COMPACTOR
-                             ? GCTracer::Scope::MC_EXTERNAL_EPILOGUE
-                             : GCTracer::Scope::SCAVENGER_EXTERNAL_EPILOGUE);
+      TRACE_GC(tracer(), GCTracer::Scope::EXTERNAL_EPILOGUE);
       VMState<EXTERNAL> state(isolate_);
       HandleScope handle_scope(isolate_);
       CallGCEpilogueCallbacks(gc_type, gc_callback_flags);