Changes to shrink the token stream representation from two words to one word.

vm/token.h

Index: vm/token.h
===================================================================
--- vm/token.h	(revision 4579)
+++ vm/token.h	(working copy)
@@ -218,6 +218,10 @@
     return (Attributes(tok) & kPseudoKeyword) != 0;
   }
 
+  static bool IsKeyword(Kind tok) {
+    return (Attributes(tok) & kKeyword) != 0;
+  }
+
   static bool IsIdentifier(Kind tok) {
     return (tok == kIDENT) || IsPseudoKeyword(tok);
   }
@@ -253,6 +257,15 @@
            (tok == kNEGATE);
   }
 
+  static bool NeedsLiteralToken(Kind tok) {
+    ASSERT(tok < kNumTokens);
+    return ((tok == Token::kINTEGER) ||
+            (tok == Token::kSTRING) ||
+            (tok == Token::kINTERPOL_VAR) ||
+            (tok == Token::kERROR) ||
+            (tok == Token::kDOUBLE));
+  }
+
  private:
   static const char* name_[kNumTokens];
   static const char* tok_str_[kNumTokens];