weblayer: disables FullscreenSizeTest#testOsk from skew tests

As it is flaky

BUG=1239002
TEST=test only change

Change-Id: I2c57244a72643717757163fd2db934fd845fdabf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3100551
Reviewed-by: Clark DuVall <cduvall@chromium.org>
Commit-Queue: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#912652}

weblayer/browser/android/javatests/skew/expectations.txt

@@ -34,6 +34,7 @@ crbug.com/1222694 [ all ] org.chromium.weblayer.test.FullscreenCallbackTest* [ S
 crbug.com/1239032 [ all ] org.chromium.weblayer.test.TabListCallbackTest#testCallbackInvokedWhenTabClosedViaWebContents [ Skip ]
 crbug.com/1239032 [ all ] org.chromium.weblayer.test.NewTabCallbackTest#testNewTabHasFocus [ Skip ]
 crbug.com/1225662 [ all ] org.chromium.weblayer.test.NavigationTest#testDestroyTabWithModalDialog [ Skip ]
+crbug.com/1239002 [ all ] org.chromium.weblayer.test.FullscreenSizeTest#testOsk [ Skip ]
 
 # Bulk disable to get bot green.
 crbug.com/1191751 [ all ] org.chromium.weblayer.test.InputTypesTest* [ Skip ]