mark AST_Var out of block scopes (#2700)

lib/compress.js

@@ -5032,10 +5032,8 @@ merge(Compressor.prototype, {
                 var init;
                 if (fixed instanceof AST_This) {
                     if (!(d.orig[0] instanceof AST_SymbolFunarg)
-                        && all(d.references, d.scope.is_block_scope() ? function(ref) {
+                        && all(d.references, function(ref) {
                             return d.scope === ref.scope;
-                        } : function(ref) {
-                            return d.scope === ref.scope.get_defun_scope();
                         })) {
                         init = fixed;
                     }

lib/scope.js

@@ -284,6 +284,10 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options){
             }
             node.thedef = sym;
             node.reference(options);
+            if (node.scope.is_block_scope()
+                && !(sym.orig[0] instanceof AST_SymbolBlockDeclaration)) {
+                node.scope = node.scope.get_defun_scope();
+            }
             return true;
         }
         // ensure mangling works if catch reuses a scope variable