Remove CONST_LEGACY VariableMode

src/globals.h

Index: src/globals.h
diff --git a/src/globals.h b/src/globals.h
index 33a4911aecbfc4a6d53812298e3bc2de60073f25..7680f27baef1e78492a62ae18452db54e19c5c63 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -886,8 +886,6 @@ enum VariableMode : uint8_t {
   // User declared variables:
   VAR,  // declared via 'var', and 'function' declarations
 
-  CONST_LEGACY,  // declared via legacy 'const' declarations
-
   LET,  // declared via 'let' declarations (first lexical)
 
   CONST,  // declared via 'const' declarations (last lexical)
@@ -926,11 +924,6 @@ inline bool IsLexicalVariableMode(VariableMode mode) {
   return mode >= LET && mode <= CONST;
 }
 
-
-inline bool IsImmutableVariableMode(VariableMode mode) {
-  return mode == CONST || mode == CONST_LEGACY;
-}
-
 enum VariableLocation : uint8_t {
   // Before and during variable allocation, a variable whose location is
   // not yet determined.  After allocation, a variable looked up as a