Update VR JS dialog golden

Updates the golden image for a VR JS dialog test that was failing due
to the image mismatch and re-enables the test.

TBR=mthiesse@chromium.org

Bug: 902319
Change-Id: I039935b788dde5b52cdf750e005fe57f9520f745
Reviewed-on: https://chromium-review.googlesource.com/c/1321794Reviewed-by: Brian Sheedy <bsheedy@chromium.org>
Commit-Queue: Brian Sheedy <bsheedy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#605933}

chrome/android/javatests/src/org/chromium/chrome/browser/vr/jsdialog/VrBrowserJavaScriptModalDialogTest.java

@@ -17,7 +17,6 @@ import org.junit.runner.RunWith;
 
 import org.chromium.base.ThreadUtils;
 import org.chromium.base.test.util.CommandLineFlags;
-import org.chromium.base.test.util.DisabledTest;
 import org.chromium.base.test.util.Feature;
 import org.chromium.base.test.util.Restriction;
 import org.chromium.chrome.browser.ChromeSwitches;
@@ -80,7 +79,6 @@ public class VrBrowserJavaScriptModalDialogTest {
     @Test
     @MediumTest
     @Feature({"Browser", "RenderTest"})
-    @DisabledTest
     public void testPromptModalDialog() throws ExecutionException, IOException {
         testModalDialogImpl(
                 "js_modal_view_vr_prompt", "prompt('Is the tree closed?', 'Hopefully not')");