avx512bw-shiftqihi-constant-1.c: Compile with -mno-gfni

Compile avx512bw-shiftqihi-constant-1.c with -mno-gfni to avoid

FAIL: gcc.target/i386/avx512bw-shiftqihi-constant-1.c scan-assembler-times vpsllw[^\n]*%zmm 1
FAIL: gcc.target/i386/avx512bw-shiftqihi-constant-1.c scan-assembler-times vpsraw[^\n]*%zmm 1
FAIL: gcc.target/i386/avx512bw-shiftqihi-constant-1.c scan-assembler-times vpsrlw[^\n]*%zmm 1
FAIL: gcc.target/i386/avx512bw-shiftqihi-constant-1.c scan-assembler-times vpsubb[^\n]*%zmm 1
FAIL: gcc.target/i386/avx512bw-shiftqihi-constant-1.c scan-assembler-times vpternlogd[^\n]*%zmm 1

when vgf2p8affineqb is generated by GFNI which is enabled by default.

	PR testsuite/126923
	* gcc.target/i386/avx512bw-shiftqihi-constant-1.c (dg-options):
	Add -mno-gfni.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>