RISC-V: Refine the testcase of vector SAT_ADD

Take scan-assembler-times for vsadd insn check instead of function body,
as we only care about if we can generate the fixed point insn vsadd.

The below test are passed for this patch.
* The rv64gcv fully regression test.

It is test only patch and obvious up to a point, will commit it
directly if no comments in next 48H.

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/rvv/autovec/binop/vec_sat_s_add-1.c: Remove
	func body check and take scan asm times instead.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_s_add-2.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_s_add-3.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_s_add-4.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add-1.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add-10.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add-11.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add-12.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add-13.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add-14.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add-15.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add-16.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add-17.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add-18.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add-19.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add-2.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add-20.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add-21.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add-22.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add-23.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add-24.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add-25.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add-26.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add-27.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add-28.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add-29.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add-3.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add-30.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add-31.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add-32.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add-4.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add-5.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add-6.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add-7.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add-8.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add-9.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add_imm-1.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add_imm-10.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add_imm-11.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add_imm-12.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add_imm-13.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add_imm-14.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add_imm-15.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add_imm-16.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add_imm-2.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add_imm-3.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add_imm-4.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add_imm-5.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add_imm-6.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add_imm-7.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add_imm-8.c: Ditto.
	* gcc.target/riscv/rvv/autovec/binop/vec_sat_u_add_imm-9.c: Ditto.

Signed-off-by: Pan Li <pan2.li@intel.com>