ia32: Clean up assure_should_be_same_requirements().
ia32: Cleanup in determine_final_cc().
ia32: Add and use the wrapper function get_irn_n_reg().

It returns a null pointer instead of a ia32_NoReg_GP.
ia32: Remove is_noreg(), which just calls is_ia32_NoReg_GP().
be: Use the global arch_no_requirement instead of generating one for each backend.
be: Cleanup in bedump.
be: Remove arch_register_req_type_normal.

This flag is plain redundant.
be: Check the register class instead of the mode in emit_be_Copy().
ia32, sparc: Remove redundant test from assure_should_be_same_requirements().

Checking the register implicitly covers checking for a data mode.
ia32: Print the verbose asm comment for asm nodes.
ia32: Cleanup in ia32_gen_ASM().
ia32: Handle early-clobber modifiers (&).