Remove failure expectations for some editing web platform tests

Bug 751952 has been fixed a while ago, so I think we can remove the
failure expectation for the forwardDelete.html test.

Additionally, there are some comments in bug 698135 that indicate the
crash is not reproducible anymore, which was the reason why there
was a failure entry for the delete.html test.

This CL removes the related entries in the TestExpectations file and
provides a new expected file for the delete.html test. It keeps,
though, a Failure entry for Mac only in the case of the delete.html,
since there are clear interoperability issues with Mac for these use
cases.

BUG=698135

Change-Id: I973b84eb1ea19fa72ba4011001aa750b73e87b0c
Reviewed-on: https://chromium-review.googlesource.com/1124461
Commit-Queue: Javier Fernandez <jfernandez@igalia.com>
Reviewed-by: Manuel Rego Casasnovas <rego@igalia.com>
Reviewed-by: Yoshifumi Inoue <yosin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#572543}

third_party/WebKit/LayoutTests/TestExpectations

@@ -1998,7 +1998,7 @@ crbug.com/490511 external/wpt/html/rendering/non-replaced-elements/the-hr-elemen
 crbug.com/692560 external/wpt/html/semantics/document-metadata/styling/LinkStyle.html [ Failure Pass ]
 crbug.com/627706 external/wpt/html/semantics/embedded-content/the-img-element/invalid-src.html [ Skip ]
 
-crbug.com/698135 external/wpt/editing/run/delete.html [ Crash Failure Timeout ]
+crbug.com/860211 [ Mac ] external/wpt/editing/run/delete.html [ Failure ]
 
 crbug.com/813098 external/wpt/editing/run/removeformat.html [ Timeout Pass ]
 
@@ -2751,7 +2751,6 @@ crbug.com/723741 virtual/threaded/http/tests/devtools/tracing/idle-callback.js [
 # These need to be updated but appear not to be related to that change.
 crbug.com/626703 http/tests/devtools/indexeddb/database-refresh-view.js [ Pass Failure ]
 crbug.com/626703 http/tests/devtools/extensions/extensions-sidebar.js [ Pass Failure ]
-crbug.com/751952 external/wpt/editing/run/forwarddelete.html [ Failure Pass Timeout ]
 crbug.com/751952 fast/text/international/complex-text-rectangle.html [ Timeout Pass ]
 crbug.com/751952 [ Mac Win ] editing/selection/modify_extend/extend_by_character.html [ Failure Pass ]
 crbug.com/751952 http/tests/devtools/console/console-uncaught-promise.js [ Pass Failure ]