Crossjumping of tablejumps

[Josef Zlomek]

> Hi,
> 
> this patch fixes breakage on s390 because of the labels in constant
> pool.

Not yet, there is a problem with ADDR_DIFF_VEC because in the constant
pool is not (label_ref:SI 52)
but (const:SI (unspec:SI [
            (label_ref:SI 52)
			        ] 100))

I know how to fix it.

Josef