When whitespace at the end of the diff is triple clicked, the diff
selection range should be normalized to just the full line.
This appears to be a regression of some sort from cb2d127 -- it is
unclear when and where this regression was introduced, but it appears
that all of the code that was introduced in that change handles cases
that no longer occur.
Bug: Issue 9368
Change-Id: I61fc39ae69f63c4bbe0d52a25a985ed588135e4b
750216571e