Disable flaky testLongpressExtendinSelectionExactResolve

TBR=donnd@chromium.org

Change-Id: I6a68584a07738a7d744a05673f09183ea04d9bfe
Bug: 1048827
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2041652Reviewed-by: Mikel Astiz <mastiz@chromium.org>
Commit-Queue: Mikel Astiz <mastiz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#738911}

chrome/android/javatests/src/org/chromium/chrome/browser/contextualsearch/ContextualSearchManagerTest.java

@@ -3228,6 +3228,7 @@ public class ContextualSearchManagerTest {
     }
 
     @Test
+    @DisabledTest(message = "See https://crbug.com/1048827")
     @SmallTest
     @Feature({"ContextualSearch"})
     @Features.EnableFeatures("ContextualSearchLongpressResolve")