Move `isDict` unit-tests from util_spec.js to primitives_spec.js

This patch moves the unit-test to the correct file, since the `isDict` function was moved PR 6683.

test/unit/primitives_spec.js

@@ -1,10 +1,9 @@
 /* globals expect, it, describe, beforeEach, Name, Dict, Ref, RefSet, Cmd,
-           jasmine */
+           jasmine, isDict */
 
 'use strict';
 
 describe('primitives', function() {
-
   describe('Name', function() {
     it('should retain the given name', function() {
       var givenName = 'Font';
@@ -146,4 +145,17 @@ describe('primitives', function() {
       expect(refset.has(anotherRef)).toBeFalsy();
     });
   });
+
+  describe('isDict', function() {
+    it('handles empty dictionaries with type check', function() {
+      var dict = new Dict();
+      expect(isDict(dict, 'Page')).toEqual(false);
+    });
+
+    it('handles dictionaries with type check', function() {
+      var dict = new Dict();
+      dict.set('Type', Name.get('Page'));
+      expect(isDict(dict, 'Page')).toEqual(true);
+    });
+  });
 });

test/unit/util_spec.js

@@ -1,22 +1,8 @@
-/* globals expect, it, describe, Dict, isDict, Name, PDFJS,
+/* globals describe, it, expect, stringToPDFString, removeNullCharacters */
-           stringToPDFString, removeNullCharacters */
 
 'use strict';
 
 describe('util', function() {
-  describe('isDict', function() {
-    it('handles empty dictionaries with type check', function() {
-      var dict = new Dict();
-      expect(isDict(dict, 'Page')).toEqual(false);
-    });
-
-    it('handles dictionaries with type check', function() {
-      var dict = new Dict();
-      dict.set('Type', Name.get('Page'));
-      expect(isDict(dict, 'Page')).toEqual(true);
-    });
-  });
-
   describe('stringToPDFString', function() {
     it('handles ISO Latin 1 strings', function() {
       var str = '\x8Dstring\x8E';