[421401] do not return an offset outside the box

This was a typical one-off problem. The forward-search for the nearest
offset (second while) should only be entered if the estimated offset is
within the box.

Reactivated the ignored tests in ContentPositionTest and
ContentPositionTableTest.

Bug: https://bugs.eclipse.org/bugs/show_bug.cgi?id=421401
Change-Id: I6004ce2539877f6a61ef4d08e0acfbe0d9f16ee6
Signed-off-by: Florian Thienel <florian@thienel.org>
4 files changed