sve2: Fix expansion of division [PR107830]

SVE has an actual division optab, and when using -Os we don't
optimize the division away.  This means that we need to distinguish
between a div which we can optimize and one we cannot even during


	PR target/107830
	* config/aarch64/
	(aarch64_vectorize_can_special_div_by_constant): Check validity during
	codegen phase as well.


	PR target/107830
	* New test.
	* New test.
3 files changed