[kaffe] move_*_const

[Kiyo Inaba]

I noticed second arguments of move_{float,double}_const in
'kaffe/kaffevm/jit3/icode.c' are changed from 0 to NULL but they are
really '0' rather than 'NULL' according to 'codeproto.h'.

So, I checked in a fix for them (to make sh-jit compilation success,
Oh yes, at least compilation is ok right now), but at the same time
move_int_const also may have same problem. But as far as sh-jit is
concerned, the portion which uses move_int_const is not involved.

My question is, can jit or jit3 for arm or sparc (these archs does not
have real neg_int and hence move_int_const should be used) be built,
right now?

Kiyo