Autosave text area, first char entry results in newline

[ptbrunet]

1. Load ​http://archive.dojotoolkit.org/nightly/dojotoolkit/dijit/tests/form/test_InlineEditBox.html
2. tab down to the second widget that starts with "I'm one big paragraph...."
3. press enter
4. press esc
5. press enter
6. press the x key
7. stop - do nothing else - look at what was entered. I see x on one line and the original text on the next line. That newline shouldn't be there.

Side effects:

1. after doing the above, pressing esc doesn't revert, but closes the box
2. the closed box doesn't show the x
3. reopen the box, the x and the first line are visible in the box but not the last line

[Douglas Hays]

(In [10082]) Fixes #4024. For FF, made the TextArea?'s body tag within the iframe editable instead of the div child so that FF doesn't mistake what is being edited.