fix(select): revert commit to fix skipping over blank disabled options

An earlier commit caused an error where the first option of a select would be skipped
over if it had a blank value. This fix adds a test case to identify this case and shows
that reverting the earlier commit causes the behavior to change. In the case of a select with
a blank disabled first option, that option should still be selected.

Relates to angular#7715

Author: Erin Altenhof-Long

test/ng/directive/selectSpec.js

@@ -1115,6 +1115,46 @@ describe('select', function() {
       });
     });
 
+    describe('disabled blank', function() {
+      it('should select disabled blank by default', function() {
+        var html = '<select ng-model="someModel" ng-options="c for c in choices">' +
+                     '<option value="" disabled>Choose One</option>' +
+                   '</select>';
+        scope.$apply(function() {
+          scope.choices = ['A', 'B', 'C'];
+        });
+
+        compile(html);
+
+        var options = element.find('option');
+        var optionToSelect = options.eq(0);
+        expect(optionToSelect.text()).toBe('Choose One');
+        expect(optionToSelect.prop('selected')).toBe(true);
+        expect(element.val()).toBe('');
+
+        dealoc(element);
+      });
+
+
+      it('should select disabled blank by default when select is required', function() {
+        var html = '<select ng-model="someModel" ng-options="c for c in choices" required>' +
+                     '<option value="" disabled>Choose One</option>' +
+                   '</select>';
+        scope.$apply(function() {
+          scope.choices = ['A', 'B', 'C'];
+        });
+
+        compile(html);
+
+        var options = element.find('option');
+        var optionToSelect = options.eq(0);
+        expect(optionToSelect.text()).toBe('Choose One');
+        expect(optionToSelect.prop('selected')).toBe(true);
+        expect(element.val()).toBe('');
+
+        dealoc(element);
+      });
+    });
 
     describe('select-many', function() {