RISC-V: Add testcases for IMM (0 ~ 31) AVL

RISC-V: Add testcases for IMM (0 ~ 31) AVL

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/rvv/vsetvl/imm_bb_prop-1.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_bb_prop-10.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_bb_prop-11.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_bb_prop-12.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_bb_prop-13.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_bb_prop-2.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_bb_prop-3.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_bb_prop-4.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_bb_prop-5.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_bb_prop-6.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_bb_prop-7.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_bb_prop-8.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_bb_prop-9.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_conflict-1.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_conflict-2.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_conflict-3.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_conflict-4.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_conflict-5.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_loop_invariant-1.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_loop_invariant-10.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_loop_invariant-11.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_loop_invariant-12.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_loop_invariant-13.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_loop_invariant-14.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_loop_invariant-15.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_loop_invariant-16.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_loop_invariant-17.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_loop_invariant-2.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_loop_invariant-3.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_loop_invariant-4.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_loop_invariant-5.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_loop_invariant-6.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_loop_invariant-7.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_loop_invariant-8.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_loop_invariant-9.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_switch-1.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_switch-2.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_switch-3.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_switch-4.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_switch-5.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_switch-6.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_switch-7.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_switch-8.c: New test.
	* gcc.target/riscv/rvv/vsetvl/imm_switch-9.c: New test.