Fix WHOPR file name reuse

[Jan Hubicka]

> > Bootstrapped/regtested x86_64-linux, OK?
> 
> I have a separate patch for the LTRANS naming issue,
> see attachment.

Haha, so we got a conflict.  I see you solved the name clash based on dumpbase.
I guess you could go ahead and commit it and I will prepare updated patch.

We solve bit of ortogonal problems here.  I still believe we need stable ltrans
names for testsuite (i.e. based on the source filename rather than blah.0.o and
blah.1.o) and for incremental compilation, so I will handle this incrementally.
And I also need the struct ltrans_partition for "proper" partitioning and sorting
by unit size.

Honza