Adds the evex-promoted opcodes vpermilps, vpermilpd, vpermd, vpermq, vpermps, vpermpd.
Adds the new AVX-512 opcodes vpermw, vpermi2d, vpermi2q, vpermi2ps, vpermi2p, vpermi2b, vpermi2w, vpermt2b, vpermt2w, vpermt2d, vpermt2q, vpermt2ps, vpermt2pd.
Adds the new size OPSZ_vex32_evex64.
Adds tests for above.
Doubles the encoding buffer size in test api.ir to 16384. Renames disassembly buffer names "buf" to "dbuf" so it doesn't shadow global encoding buffer "buf".
Opcodes have been checked against llvm-mc, binutils/gas/objdump and capstone.
Issue: #1312