LoongArch: Add more numbers supported for {x}vldi

LoongArch: Add more numbers supported for {x}vldi

When the most significant bit of the 13 bit immediate value in LoongArch
{x}vldi isntruction is set 1, it can generate different numbers based on
the algorithm.  This patch adds to support these numbers to be
generated by {x}vldi instruction.

gcc/ChangeLog:

	* config/loongarch/constraints.md: Update constraint YI to support
	more numbers.
	* config/loongarch/loongarch-protos.h
	(loongarch_const_vector_vrepli): Rename.
	(loongarch_const_vector_vldi): Ditto.
	* config/loongarch/loongarch.cc (VLDI_NEG_MASK): New macro.
	(loongarch_parse_vldi_const): New function to check if numbers can
	be generated by {x}vldi instruction.
	(loongarch_const_vector_vrepli): Rename.
	(loongarch_const_vector_vldi): Use above function.
	(loongarch_const_insns): Call renamed function.
	(loongarch_split_vector_move_p): Ditto.
	(loongarch_output_move): Ditto.

gcc/testsuite/ChangeLog:

	* gcc.target/loongarch/vector/lasx/lasx-builtin.c: Replace xvrepli
	with xvldi.
	* gcc.target/loongarch/vector/lasx/lasx-vec-init-2.c: Fix test.
	* gcc.target/loongarch/vector/lsx/lsx-builtin.c: Repalce vrepli with
	vldi.
	* gcc.target/loongarch/vrepli.c: Ditto.
	* gcc.target/loongarch/vector/lasx/lasx-xvldi-2.c: New test.
	* gcc.target/loongarch/vector/lsx/lsx-vldi-2.c: New test.