Here's the blamelist: http://trac.webkit.org/log/?verbose=on&rev=120110&stop_rev=120108.
http://trac.webkit.org/changeset/120108/ seems like the only possible culprit.
In Mac and Linux debug the actual results end with two newlines (ie 0x0a, 0x0a). In the expected results there is a space on the last line, ie the last three bytes are 0x0a 0x20 0x0a and the file is one byte larger.
Marked LayoutTest bugs, bugs with Chromium IDs, and some others as WontFix. Test failure bugs still are trackable via TestExpectations or disabled unit tests.