Disable SafeBrowsingTest#testSafeBrowsingWhitelistHardcodedWebUiPages

Test flaky in:
https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/android-marshmallow-arm64-rel

TBR=ntfschr@chromium.org,changwan@chromium.org,boliu@chromium.org

Bug: 855732
Change-Id: If4fe61aa767bd92229692bddb4659901fa5b2da5
Reviewed-on: https://chromium-review.googlesource.com/1117065Reviewed-by: Juan Antonio Navarro Pérez <perezju@chromium.org>
Commit-Queue: Juan Antonio Navarro Pérez <perezju@chromium.org>
Cr-Commit-Position: refs/heads/master@{#570759}

android_webview/javatests/src/org/chromium/android_webview/test/SafeBrowsingTest.java

@@ -507,6 +507,7 @@ public class SafeBrowsingTest {
         assertTargetPageHasLoaded(MALWARE_PAGE_BACKGROUND_COLOR);
     }
 
+    @DisabledTest(message = "crbug.com/855732")
     @Test
     @SmallTest
     @Feature({"AndroidWebView"})