ir: Use mode_is_float()/mode_is_int() instead of get_mode_sort()/->sort == irms_float_number/irms_int_number.

There are still similar problems left.

* This corrects the requirements of fStore.

This properly models the data dependencies and avoids keep edges.

Determine the pos from the node to push.

This replaces several 1/0 and true/false by yes/no.

Many x87 nodes do not need the x87-specific attributes.

Some instructions liks shifts or out/in can only handle some forms of
immediates. Make matchers respect that.

This fixes backend/ia32_shl.c, although the real question here is
probably why that program wasn't folded to a point where the middleend
would reduce the shift amount anyway because of the modulo shift mode.

Add callbacks on functions that really need them instead.

When creating an entity for a floatingpoint constant, first try to reduce the size, then check, whether it already exists.
This way only a single entity is created for e.g. a double and a float 1.0.