RISC-V: Reuse test name for vx combine test data [NFC]

RISC-V: Reuse test name for vx combine test data [NFC]

For run test, we have a name like add/sub to indicate
the testcase.  So we can reuse this to identify the
test data instead of a new one.

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_binary_data.h: Take
	test name for the vx combine test data.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx_vadd-run-1-i16.c: Leverage
	the test name to identify the test data.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx_vadd-run-1-i32.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx_vadd-run-1-i64.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx_vadd-run-1-i8.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx_vadd-run-1-u16.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx_vadd-run-1-u32.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx_vadd-run-1-u64.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx_vadd-run-1-u8.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx_vsub-run-1-i16.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx_vsub-run-1-i32.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx_vsub-run-1-i64.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx_vsub-run-1-i8.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx_vsub-run-1-u16.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx_vsub-run-1-u32.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx_vsub-run-1-u64.c: Ditto.
	* gcc.target/riscv/rvv/autovec/vx_vf/vx_vsub-run-1-u8.c: Ditto.

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