Support Intel AVX-VNNI-INT8

gas/
        * NEWS: Support Intel AVX-VNNI-INT8.
	* config/tc-i386.c: Add avx_vnni_int8.
	* doc/c-i386.texi: Document avx_vnni_int8.
	* testsuite/gas/i386/avx-vnni-int8-intel.d: New file.
	* testsuite/gas/i386/avx-vnni-int8.d: Likewise.
	* testsuite/gas/i386/avx-vnni-int8.s: Likewise.
	* testsuite/gas/i386/x86-64-avx-vnni-int8-intel.d: Likewise.
	* testsuite/gas/i386/x86-64-avx-vnni-int8.d: Likewise.
	* testsuite/gas/i386/x86-64-avx-vnni-int8.s: Likewise.
	* testsuite/gas/i386/i386.exp: Run AVX VNNI INT8 tests.

opcodes/
	* i386-dis.c: (PREFIX_VEX_0F3850) New.
	(PREFIX_VEX_0F3851): Likewise.
	(VEX_W_0F3850_P_0): Likewise.
	(VEX_W_0F3850_P_1): Likewise.
	(VEX_W_0F3850_P_2): Likewise.
	(VEX_W_0F3850_P_3): Likewise.
	(VEX_W_0F3851_P_0): Likewise.
	(VEX_W_0F3851_P_1): Likewise.
	(VEX_W_0F3851_P_2): Likewise.
	(VEX_W_0F3851_P_3): Likewise.
	(VEX_W_0F3850): Delete.
	(VEX_W_0F3851): Likewise.
	(prefix_table): Add PREFIX_VEX_0F3850 and PREFIX_VEX_0F3851.
	(vex_table): Add PREFIX_VEX_0F3850 and PREFIX_VEX_0F3851,
	delete VEX_W_0F3850 and VEX_W_0F3851.
	(vex_w_table): Add VEX_W_0F3850_P_0, VEX_W_0F3850_P_1, VEX_W_0F3850_P_2
	VEX_W_0F3850_P_3, VEX_W_0F3851_P_0, VEX_W_0F3851_P_1, VEX_W_0F3851_P_2
	and VEX_W_0F3851_P_3, delete VEX_W_0F3850 and VEX_W_0F3851.
	* i386-gen.c: (cpu_flag_init): Add CPU_AVX_VNNI_INT8_FLAGS
	and CPU_ANY_AVX_VNNI_INT8_FLAGS.
	(cpu_flags): Add CpuAVX_VNNI_INT8.
	* i386-opc.h (CpuAVX_VNNI_INT8): New.
	* i386-opc.tbl: Add Intel AVX_VNNI_INT8 instructions.
	* i386-init.h: Regenerated.
	* i386-tbl.h: Likewise.