Detect previously checked RadioMenuItem on the fly.
Matches how _RadioButtonMixin works.
Refs #17519.

Also updating _RadioButtonMixin.js to specify that it only needs dojo/query!css2.
Set height:100% on #dijitEditorBody in addition to <body>.
Note that usually #dijitEditorBody is actually the <div> inside the <body>.

Setting height:100% on the <div> fixes the Chrome problem where typing ctrl-A
and then some characters locks up the editor.   Doesn't seem to affect IE or FF.
The scrollbar still seems to work (showing up when the editor content overflows).

Refs #16804, fixes #17559.
Fixes regression from b61b56813dc0c922976ca783496c374b81ca3b58.
Fixes and refactorings for Editor on Firefox.

Fixes Editor_a11y.html regression test failure and removes firefox specific code branches:

- make FF use contentEditable (like other browsers) rather than designMode
- make FF use nested <div> inside of <body> (inside of <iframe>), just like other browsers
- expand tabbing helper code (both for tabbing/shift-tabbing into and out of the iframe) to run on all browsers, not just IE
- reduce the number of branches in focus(), so that Chrome and FF use same path

Fixes #10415, #17560.
Refs #11898.
avoid spurious failure on chrome where italic button is checked,
and stop using internal editor method to position caret, refs #9460
Remove trailing whitespace from Editor value.
Fixes test failures on Chrome in Editor_mouse.html, Editor_a11y.html.
Fixes #17561.
Add test case for clearing editor then focusing it.  Refs #10268.
Remove _cursorToStart code that's apparently no longer needed.  Fixes #17568.
Add test case for setting editor value before focusing it, refs #9151.
Also removing related &nbsp code that no longer seems necessary.
fix padding miscalculation, thanks JaeTea666, fixes #17571
ValidationTextBox#pattern changes should update state

Fixes #17408.
Do not copy properties indiscriminately from `constraints`

Fixes #17250.
Fix dijit Editor in cross-domain pages with document.domain set

Fixes #17529.
Support unprefixed pointer events

Refs #17600
Fix bad module IDs in DnD tests

Fixes #17601
Target IE9 only for zone security workaround

IE10 does not have this issue and some unit tests break with this "fix".

Refs #16633.
Make necessary additions to Editor for modern Trident

Refs #17311.
Fix invalid test PHP

Fixes #17603.
keypress event does not fire for non-character keys in Firefox

This matches the DOM 3 Events specification.

Fixes #17604.
Work around Chrome bug for Textarea robot test

The bug is an issue with TabContainer in Chrome blowing its width.
This does not fix the real bug, it just makes the unrelated test
failure stop happening.

Fixes #17605.
Fix formatblock command in IE9+

Fixes FontChoice plugin test failures

Refs #17311.
Massively speed up robot validationMessages tests

Refs #7681