typechange tests for git apply (currently failing)

typechange tests for git apply (currently failing)

I've found that git apply is incapable of handling patches
involving object type changes to the same path.

Of course git itself is perfectly capable of making commits that
generate these changes, as it only tracks trees states.  It's
just that the diffs between them are less useful if they can't
be applied.

Some of these are rare, but I've hit one of them (file becoming
a symlink) recently in real-world usage, and was inspired to
find more potential breakages :)

I'm not sure when I'll have time to fix these myself and I'm not
very familiar with the apply code.   So if someone could get
some or all of these cases working, they would be my hero :)

Some of these are what I would refer to as corner-cases from
hell.  Most (if not all) other systems fail some of these.  In
fact, they aren't even capable of representing most of these
changes in their histories; much less being able to handle
patches to that effect.

Signed-off-by: Eric Wong <normalperson@yhbt.net>
Signed-off-by: Junio C Hamano <junkio@cox.net>