VM: Clear all *_to_retain maps when resetting the precompiler state

runtime/vm/precompiler.cc

Index: runtime/vm/precompiler.cc
diff --git a/runtime/vm/precompiler.cc b/runtime/vm/precompiler.cc
index e45c04cf08662ca5dcda050f1196e28a4b9b0bce..0c57d8921abe50c22bf02a53d7693f505a1f6f7a 100644
--- a/runtime/vm/precompiler.cc
+++ b/runtime/vm/precompiler.cc
@@ -2959,7 +2959,13 @@ void Precompiler::ResetPrecompilerState() {
   ASSERT(pending_functions_.Length() == 0);
   sent_selectors_.Clear();
   enqueued_functions_.Clear();
+
+  classes_to_retain_.Clear();
   consts_to_retain_.Clear();
+  fields_to_retain_.Clear();
+  functions_to_retain_.Clear();
+  typeargs_to_retain_.Clear();
+  types_to_retain_.Clear();
 
   Library& lib = Library::Handle(Z);
   Class& cls = Class::Handle(Z);