LiveEdit: optimize substring comparison

src/isolate.h

Index: src/isolate.h
diff --git a/src/isolate.h b/src/isolate.h
index 35ffcb4445cf594546b62f12bac74a7afb3025b1..49391a331ad76de9bd3591e89f4bc216b71e5960 100644
--- a/src/isolate.h
+++ b/src/isolate.h
@@ -869,14 +869,6 @@ class Isolate {
 
   RuntimeState* runtime_state() { return &runtime_state_; }
 
-  StringInputBuffer* liveedit_compare_substrings_buf1() {
-    return &liveedit_compare_substrings_buf1_;
-  }
-
-  StringInputBuffer* liveedit_compare_substrings_buf2() {
-    return &liveedit_compare_substrings_buf2_;
-  }
-
   StaticResource<SafeStringInputBuffer>* compiler_safe_string_input_buffer() {
     return &compiler_safe_string_input_buffer_;
   }
@@ -1140,8 +1132,6 @@ class Isolate {
   ThreadManager* thread_manager_;
   AstSentinels* ast_sentinels_;
   RuntimeState runtime_state_;
-  StringInputBuffer liveedit_compare_substrings_buf1_;
-  StringInputBuffer liveedit_compare_substrings_buf2_;
   StaticResource<SafeStringInputBuffer> compiler_safe_string_input_buffer_;
   Builtins builtins_;
   StringTracker* string_tracker_;