Adding smi cache

src/parsing/scanner.h

Index: src/parsing/scanner.h
diff --git a/src/parsing/scanner.h b/src/parsing/scanner.h
index b2b1a8a3f48a348b5fb8c44591d571749a0ac98f..f3fc02558e714da475f811b4504e649897b5a993 100644
--- a/src/parsing/scanner.h
+++ b/src/parsing/scanner.h
@@ -284,7 +284,7 @@ class Scanner {
   }
 
   // Returns the value of the last smi that was scanned.
-  int smi_value() const { return current_.smi_value_; }
+  uint32_t smi_value() const { return current_.smi_value_; }
 
   // Seek forward to the given position.  This operation does not
   // work in general, for instance when there are pushed back
@@ -487,7 +487,7 @@ class Scanner {
     Location location;
     LiteralBuffer* literal_chars;
     LiteralBuffer* raw_literal_chars;
-    int smi_value_;
+    uint32_t smi_value_;
     Token::Value token;
   };