Provide a mechanism for naming a hash table so that it can be used in DumpStats to identify the tab…

runtime/vm/symbols.cc

Index: runtime/vm/symbols.cc
diff --git a/runtime/vm/symbols.cc b/runtime/vm/symbols.cc
index bad8f741f669a9a4a50e599901d67d78f8dc67fd..5f22e7fe8163b2911b21c3be84ad74110464cde4 100644
--- a/runtime/vm/symbols.cc
+++ b/runtime/vm/symbols.cc
@@ -134,6 +134,8 @@ RawString* ConcatString::ToSymbol() const {
 
 class SymbolTraits {
  public:
+  static const char* Name() { return "SymbolTraits"; }
+
   static bool IsMatch(const Object& a, const Object& b) {
     return String::Cast(a).Equals(String::Cast(b));
   }