RISC-V: Fix another vf FP16 combine run test failures

RISC-V: Fix another vf FP16 combine run test failures

Like Robin's fix for vf combine f16.c run tests, there is still
another failures similar.  This patch would like to fix it as
previous.

will commit it directly if the CI agrees.

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/rvv/autovec/vx_vf/vf_vfwnmacc-run-1-f16.c:
	Add zvfh requirements and options.
	* gcc.target/riscv/rvv/autovec/vx_vf/vf_vfwnmsac-run-1-f16.c:
	Ditto.

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