The flag has been superseded by the immediate kind.

It is now required to set a (relocation) kind when entity != NULL.
Adds IMM_ADDR, PICBASE_REL kinds to differentiate between absolute
addresses and picbase relative addresses. Maintain the no_picbase_adjust
flag in parallel for testing. We should be able to remove it in a
subsequent commit.

We can simply patch the Immediate node attached to the Call, all cases
without an Immediate node need PIC adjustment anyway.

rolw has no constraints for the registers.
Also it is faster on some processors.
On the other hand, xchgb is shorter, so try to replace rolw in the peephole pass, when optimizing for size and the register permits.

This fixes opt/fehler298.c.

Otherwise, the code would be broken.

This fixes opt/fehler299.c.

The optimization does not work properly for relation_true and relation_false.

* Parameter entities are shifted by the correct amount.
* All Return nodes are lowered, if there is more than one.