Fix bug where inline diffs are incorrect when jumping changes

Collapse them upon reload of the file list.

Change-Id: I2b0e115176db83169324f2d9289aae2665886f8c

polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.html

@@ -168,7 +168,7 @@ limitations under the License.
           <span class="removed">-[[file.lines_deleted]]</span>
         </div>
       </div>
-      <gr-diff id="diff" hidden
+      <gr-diff hidden
           change-num="[[changeNum]]"
           patch-range="[[patchRange]]"
           path="[[file.__path]]"

polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.js

@@ -60,6 +60,8 @@
         return Promise.resolve();
       }
 
+      this._collapseAllDiffs();
+
       var promises = [];
       var _this = this;