RFA: Fix PR rtl-optimization/60651

[Eric Botcazou]

> As described in the PR, this patch fixes a wrong-code bug by making the
> order of emitted mode switching instructions more consistet & predictable.

I don't understand this change (but I'm not a specialist of mode switching): 
currently the mode setting sequence is always emitted before the insns that 
need it but, with the change, if an insn right after a NOTE_BASIC_BLOCK note 
needs it, if will be emitted either before it (if insn_ptr is the insn) or 
after it (if insn_ptr is the NOTE_BASIC_BLOCK note).

-- 
Eric Botcazou