Reorder VariableMode enums to slightly simplify IsLexicalVariableMode()

Change-Id: I0f4756efdaa9468bcbd88949ddb2e2d7cae3ce06
Reviewed-on: https://chromium-review.googlesource.com/568917Reviewed-by: Sathya Gunasekaran <gsathya@chromium.org>
Commit-Queue: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46610}

src/globals.h

@@ -955,12 +955,12 @@ const double kMaxSafeInteger = 9007199254740991.0;  // 2^53-1
 // The order of this enum has to be kept in sync with the predicates below.
 enum VariableMode : uint8_t {
   // User declared variables:
-  VAR,  // declared via 'var', and 'function' declarations
-
   LET,  // declared via 'let' declarations (first lexical)
 
   CONST,  // declared via 'const' declarations (last lexical)
 
+  VAR,  // declared via 'var', and 'function' declarations
+
   // Variables introduced by the compiler:
   TEMPORARY,  // temporary variables (not user-visible), stack-allocated
               // unless the scope as a whole has forced context allocation
@@ -1014,13 +1014,14 @@ inline bool IsDynamicVariableMode(VariableMode mode) {
 
 
 inline bool IsDeclaredVariableMode(VariableMode mode) {
-  STATIC_ASSERT(VAR == 0);  // Implies that mode >= VAR.
-  return mode <= CONST;
+  STATIC_ASSERT(LET == 0);  // Implies that mode >= LET.
+  return mode <= VAR;
 }
 
 
 inline bool IsLexicalVariableMode(VariableMode mode) {
-  return mode >= LET && mode <= CONST;
+  STATIC_ASSERT(LET == 0);  // Implies that mode >= LET.
+  return mode <= CONST;
 }
 
 enum VariableLocation : uint8_t {