Remove unused VariableLocation::GLOBAL.

src/globals.h

Index: src/globals.h
diff --git a/src/globals.h b/src/globals.h
index 52a1d981ffc0e2dd1ecface1df74a195a9ee6315..1eddb7f7389ca59732b234fb2392b6f5d2ba3a45 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -943,12 +943,6 @@ enum VariableLocation : uint8_t {
   // corresponding scope.
   CONTEXT,
 
-  // An indexed slot in a script context that contains a respective global
-  // property cell.  name() is the variable name, index() is the variable
-  // index in the context object on the heap, starting at 0.  scope() is the
-  // corresponding script scope.
-  GLOBAL,
-
   // A named slot in a heap context.  name() is the variable name in the
   // context object on the heap, with lookup starting at the current
   // context.  index() is invalid.