Bug 1348073 - Part 4. Unnecessary VK_RIGHT to move caret on non-visual frame that is whitespace only node. r=masayuki

Since we enable lazy frame construction for editable region, whitespace only node might not have frame even if editable.  This test has whitespace only node into contenteditable, we need adjust caret operation for this test.

MozReview-Commit-ID: GQfKiYdYOdi

--HG--
extra : rebase_source : 0685d724f6af050d79c1cf007c7ee48c05da14ac

editor/libeditor/tests/test_bug430392.html

@@ -34,7 +34,6 @@ function test() {
   var tests = [["adding returns", () => {
     getSelection().collapse(edit.firstChild, 0);
     synthesizeKey("VK_RIGHT", {});
-    synthesizeKey("VK_RIGHT", {});
     synthesizeKey("VK_RETURN", {});
     synthesizeKey("VK_RETURN", {});
     synthesizeKey("VK_BACK_SPACE", {});
@@ -45,7 +44,6 @@ function test() {
   ["adding shift-returns", () => {
     getSelection().collapse(edit.firstChild, 0);
     synthesizeKey("VK_RIGHT", {});
-    synthesizeKey("VK_RIGHT", {});
     synthesizeKey("VK_RETURN", {shiftKey: true});
     synthesizeKey("VK_RETURN", {shiftKey: true});
     synthesizeKey("VK_BACK_SPACE", {});