Add usage and collision details to the hash table data structure in order to determine effectivenes…

runtime/vm/symbols.cc

Index: runtime/vm/symbols.cc
diff --git a/runtime/vm/symbols.cc b/runtime/vm/symbols.cc
index 5fb54bc0d91b4140d8c820410e52e2ee369c7168..04d608851332e2eabc183c1afc7cebe1c91927db 100644
--- a/runtime/vm/symbols.cc
+++ b/runtime/vm/symbols.cc
@@ -148,6 +148,7 @@ RawString* ConcatString::ToSymbol() const {
 class SymbolTraits {
  public:
   static const char* Name() { return "SymbolTraits"; }
+  static bool ReportStats() { return false; }
 
   static bool IsMatch(const Object& a, const Object& b) {
     const String& a_str = String::Cast(a);