vect: generate suitable convert insn for int -> int, float -> float and int <-> float.

vect: generate suitable convert insn for int -> int, float -> float and int <-> float.

gcc/ChangeLog:

	PR target/107432
	* tree-vect-generic.cc
	(expand_vector_conversion): Support convert for int -> int,
	float -> float and int <-> float.
	* tree-vect-stmts.cc (vectorizable_conversion): Wrap the
	indirect convert part.
	(supportable_indirect_convert_operation): New function.
	* tree-vectorizer.h (supportable_indirect_convert_operation):
	Define the new function.

gcc/testsuite/ChangeLog:

	PR target/107432
	* gcc.target/i386/pr107432-1.c: New test.
	* gcc.target/i386/pr107432-2.c: Ditto.
	* gcc.target/i386/pr107432-3.c: Ditto.
	* gcc.target/i386/pr107432-4.c: Ditto.
	* gcc.target/i386/pr107432-5.c: Ditto.
	* gcc.target/i386/pr107432-6.c: Ditto.
	* gcc.target/i386/pr107432-7.c: Ditto.