Use objects for hash value tracking

The use of arrays was incorrect for the data type and causing problems when hash keys conflicted with array behaviors.

Fixes #1194

lib/handlebars/compiler/javascript-compiler.js

@@ -503,7 +503,7 @@ JavaScriptCompiler.prototype = {
     if (this.hash) {
       this.hashes.push(this.hash);
     }
-    this.hash = {values: [], types: [], contexts: [], ids: []};
+    this.hash = {values: {}};
   },
   popHash: function() {
     let hash = this.hash;

spec/regressions.js

@@ -277,4 +277,15 @@ describe('Regressions', function() {
 
     shouldCompileTo(string, { listOne: ['a'], listTwo: ['b']}, 'ab', '');
   });
+
+  it('should allow hash with protected array names', function() {
+    var obj = {array: [1], name: 'John'};
+    var helpers = {
+      helpa: function(options) {
+        return options.hash.length;
+      }
+    };
+
+    shouldCompileTo('{{helpa length="foo"}}', [obj, helpers], 'foo');
+  });
 });