Fix new branch dropdown position and size

Fix https://gitlab.com/gitlab-org/gitlab-ce/issues/32096

app/views/projects/branches/new.html.haml

@@ -17,10 +17,12 @@
       .help-block.text-danger.js-branch-name-error
   .form-group
     = label_tag :ref, 'Create from', class: 'control-label'
-    .col-sm-10.dropdown.create-from
+    .col-sm-10.create-from
+      .dropdown
         = hidden_field_tag :ref, default_ref
-      = button_tag type: 'button', title: default_ref, class: 'dropdown-toggle form-control js-branch-select', required: true, data: { toggle: 'dropdown', selected: default_ref, field_name: 'ref' } do
+        = button_tag type: 'button', title: default_ref, class: 'dropdown-menu-toggle wide form-control js-branch-select', required: true, data: { toggle: 'dropdown', selected: default_ref, field_name: 'ref' } do
           .text-left.dropdown-toggle-text= default_ref
+          = icon('chevron-down')
         = render 'shared/ref_dropdown', dropdown_class: 'wide'
       .help-block Existing branch name, tag, or commit SHA
   .form-actions

spec/features/projects/branches/new_branch_ref_dropdown_spec.rb

@@ -3,7 +3,7 @@ require 'spec_helper'
 describe 'New Branch Ref Dropdown', :js, :feature do
   let(:user) { create(:user) }
   let(:project) { create(:project, :public) }
-  let(:toggle) { find('.create-from .dropdown-toggle') }
+  let(:toggle) { find('.create-from .dropdown-menu-toggle') }
 
   before do
     project.add_master(user)