aarch64: PR target/99037 Fix RTL represntation in move_lo_quad patterns

aarch64: PR target/99037 Fix RTL represntation in move_lo_quad patterns

This patch fixes the RTL representation of the move_lo_quad patterns to use aarch64_simd_or_scalar_imm_zero
for the zero part rather than a vec_duplicate of zero or a const_int 0.
The expander that generates them is also adjusted so that we use and match the correct const_vector forms throughout.

Co-Authored-By: Jakub Jelinek <jakub@redhat.com>
gcc/ChangeLog:

	PR target/99037
	* config/aarch64/aarch64-simd.md (move_lo_quad_internal_<mode>): Use
	aarch64_simd_or_scalar_imm_zero to match zeroes.  Remove pattern
	matching const_int 0.
	(move_lo_quad_internal_be_<mode>): Likewise.
	(move_lo_quad_<mode>): Update for the above.
	* config/aarch64/iterators.md (VQ_2E): Delete.

gcc/testsuite/ChangeLog:

	PR target/99808
	* gcc.target/aarch64/pr99808.c: New test.