The opt_manage framework didn't really do much except assuring that some
analysis info is computed before a pass starts. We can achieve this
simpler by providing an assure_irg_properties function.
This commit also fixes some places where analysis info was potentially
not invalidated before.

Noone was really using the return values anyway. This change makes the
API more consistent.

This makes it consistent with other firm analyse functions. Also removes
the unnecessary return value.

graph_properties are things that a transformation may destroy but which
can be easily recalculated.

graph_constraints are set after lowering phases have been running and
forbid certain constructs that no (later) transformation is allowed to construct

First it is unclear what is a good way to deconstruct a program into extended
basic blocks, also none of our optimizations works on extended basic
blocks.

This call initializes the node_nr with a random value on startup. This
lets you test wether the compile behaves deterministically regardless of
node numbers (which isn't always the case right now).

This makes the produced assembler independent from fragile node numbers.
It's also a little bit easier to read.

Also factor out code that emits the label and comment at the beginning
of a basic block.

It probably was true when the start block had itself as predecessor.