Use a single Token::INIT for all variable initialization

src/token.h

Index: src/token.h
diff --git a/src/token.h b/src/token.h
index 2443e842386a04b9c6a8f11d1b4f6336ab6314c7..88d4eabbd572c504bbfafc2f219ff2e7cfa4ad91 100644
--- a/src/token.h
+++ b/src/token.h
@@ -50,10 +50,7 @@ namespace internal {
   /* IsAssignmentOp() and Assignment::is_compound() relies on */     \
   /* this block of enum values being contiguous and sorted in the */ \
   /* same order! */                                                  \
-  T(INIT_VAR, "=init_var", 2)                   /* AST-use only. */  \
-  T(INIT_LET, "=init_let", 2)                   /* AST-use only. */  \
-  T(INIT_CONST, "=init_const", 2)               /* AST-use only. */  \
-  T(INIT_CONST_LEGACY, "=init_const_legacy", 2) /* AST-use only. */  \
+  T(INIT, "=init", 2) /* AST-use only. */                            \
   T(ASSIGN, "=", 2)                                                  \
   T(ASSIGN_BIT_OR, "|=", 2)                                          \
   T(ASSIGN_BIT_XOR, "^=", 2)                                         \
@@ -214,7 +211,7 @@ class Token {
   }
 
   static bool IsAssignmentOp(Value tok) {
-    return INIT_VAR <= tok && tok <= ASSIGN_MOD;
+    return INIT <= tok && tok <= ASSIGN_MOD;
   }
 
   static bool IsBinaryOp(Value op) {