RISC-V: Tweak the asm check test of vx combine on GR2VR cost [NFC]

RISC-V: Tweak the asm check test of vx combine on GR2VR cost [NFC]

Tweak the asm check with define T uint8_t for adding more
vx test easily, as well as less possibility to make mistake.

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

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/rvv/autovec/vx_vf/vx-1-i16.c: Extract
	define T as type for testing.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-1-i32.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-1-i64.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-1-i8.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-1-u16.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-1-u32.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-1-u64.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-1-u8.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-2-i16.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-2-i32.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-2-i64.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-2-i8.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-2-u16.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-2-u32.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-2-u64.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-2-u8.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-3-i16.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-3-i32.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-3-i64.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-3-i8.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-3-u16.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-3-u32.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-3-u64.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-3-u8.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-4-i16.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-4-i32.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-4-i64.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-4-i8.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-4-u16.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-4-u32.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-4-u64.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-4-u8.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-5-i16.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-5-i32.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-5-i64.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-5-i8.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-5-u16.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-5-u32.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-5-u64.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-5-u8.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-6-i16.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-6-i32.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-6-i64.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-6-i8.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-6-u16.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-6-u32.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-6-u64.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx-6-u8.c: Ditto.

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