Disable org.chromium.chrome.browser.ntp.NewTabPageTest#testRender

This test has been flaky for many cycles:
https://build.chromium.org/p/chromium.linux/builders/Android%20Tests
https://build.chromium.org/p/chromium.linux/builders/Android%20Tests%20%28dbg%29

Disabling it for now is probably the best option.
This CL disables it according to the instruction here:
https://www.chromium.org/developers/tree-sheriffs/sheriff-details-chromium/handling-a-failing-test

TBR=dgn@chromium.org
NOTRY=true

Bug: 769265
Change-Id: Ieeeeb6e3bd56b5878ce4cc7e687c9f69abc08bdd
Reviewed-on: https://chromium-review.googlesource.com/688582
Commit-Queue: Xida Chen <xidachen@chromium.org>
Reviewed-by: Xida Chen <xidachen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#504863}

chrome/android/javatests/src/org/chromium/chrome/browser/ntp/NewTabPageTest.java

@@ -130,8 +130,9 @@ public class NewTabPageTest {
     }
 
     @Test
-    @MediumTest
-    @Feature({"NewTabPage", "RenderTest"})
+    // @MediumTest
+    // @Feature({"NewTabPage", "RenderTest"})
+    @DisabledTest
     @CommandLineFlags.Add("disable-features=NTPCondensedLayout")
     public void testRender() throws IOException {
         mActivityTestRule.getInstrumentation().waitForIdleSync();