[heap] Remove dead counters and move regexp code counter to Isolate

src/isolate.h

Index: src/isolate.h
diff --git a/src/isolate.h b/src/isolate.h
index 2acfd6287c261c58e083cb0caa00dc91a233a312..ffbda4363725e1fbb75d29e869f2cab203e60a78 100644
--- a/src/isolate.h
+++ b/src/isolate.h
@@ -912,6 +912,11 @@ class Isolate {
 
   RegExpStack* regexp_stack() { return regexp_stack_; }
 
+  size_t total_regexp_code_generated() { return total_regexp_code_generated_; }
+  void IncreaseTotalRegexpCodeGenerated(int size) {
+    total_regexp_code_generated_ += size;
+  }
+
   List<int>* regexp_indices() { return &regexp_indices_; }
 
   unibrow::Mapping<unibrow::Ecma262Canonicalize>*
@@ -1484,6 +1489,8 @@ class Isolate {
 
   bool allow_atomics_wait_;
 
+  size_t total_regexp_code_generated_;
+
   friend class ExecutionAccess;
   friend class HandleScopeImplementer;
   friend class HeapTester;