encgen: evex 2/3 (potentially mixed) x/y/zmm regs+optional imm8, rcsae.
encgen: evex 2/3 (potentially mixed) x/y/zmm regs+optional imm8, rcsae.

  * handled 166 new cases -> 89.9%

Change-Id: I4e3c5b8fdccfd5bfedb27436c66d6edc3956bc84
(cherry picked from commit 242c87c56b26457e2ed30f7671984112ed5e6386)

intelxed/xed,intelxed/xed,intelxed/xed,intelxed/xed