[RISC-V] Drop scan-tests of marginal value

[RISC-V] Drop scan-tests of marginal value

gcc/testsuite
	* gcc.target/riscv/rvv/vsetvl/avl_single-37.c: Drop unnecessary output
	test(s).
	* gcc.target/riscv/rvv/vsetvl/vlmax_phi-1.c: Likewise.
	* gcc.target/riscv/rvv/vsetvl/vlmax_phi-2.c: Likewise.
	* gcc.target/riscv/rvv/vsetvl/vlmax_phi-3.c: Likewise.
	* gcc.target/riscv/rvv/vsetvl/vlmax_phi-4.c: Likewise.
	* gcc.target/riscv/rvv/vsetvl/vlmax_phi-5.c: Likewise.
	* gcc.target/riscv/rvv/vsetvl/vlmax_phi-6.c: Likewise.
	* gcc.target/riscv/rvv/vsetvl/vlmax_phi-7.c: Likewise.
	* gcc.target/riscv/rvv/vsetvl/vlmax_phi-8.c: Likewise.
	* gcc.target/riscv/rvv/vsetvl/vlmax_phi-9.c: Likewise.
	* gcc.target/riscv/rvv/vsetvl/vlmax_phi-10.c: Likewise.
	* gcc.target/riscv/rvv/vsetvl/vlmax_phi-11.c: Likewise.
	* gcc.target/riscv/rvv/vsetvl/vlmax_phi-12.c: Likewise.
	* gcc.target/riscv/rvv/vsetvl/vlmax_phi-13.c: Likewise.
	* gcc.target/riscv/rvv/vsetvl/vlmax_phi-14.c: Likewise.
	* gcc.target/riscv/rvv/vsetvl/vlmax_phi-15.c: Likewise.
	* gcc.target/riscv/rvv/vsetvl/vlmax_phi-16.c: Likewise.
	* gcc.target/riscv/rvv/vsetvl/vlmax_phi-17.c: Likewise.
	* gcc.target/riscv/rvv/vsetvl/vlmax_phi-18.c: Likewise.
	* gcc.target/riscv/rvv/vsetvl/vlmax_phi-19.c: Likewise.
	* gcc.target/riscv/rvv/vsetvl/vlmax_phi-20.c: Likewise.
	* gcc.target/riscv/rvv/vsetvl/vlmax_phi-21.c: Likewise.
	* gcc.target/riscv/rvv/vsetvl/vlmax_phi-22.c: Likewise.
	* gcc.target/riscv/rvv/vsetvl/vlmax_phi-23.c: Likewise.
	* gcc.target/riscv/rvv/vsetvl/vlmax_phi-24.c: Likewise.
	* gcc.target/riscv/rvv/vsetvl/vlmax_phi-25.c: Likewise.
	* gcc.target/riscv/rvv/vsetvl/vlmax_phi-26.c: Likewise.
	* gcc.target/riscv/rvv/vsetvl/vlmax_phi-27.c: Likewise.
	* gcc.target/riscv/rvv/vsetvl/vlmax_phi-28.c: Likewise.