Intel APX NDD instructions are encoded using EVEX encoding. The goal of this PR is to enable optimized instruction encoding for Intel APX NDD instructions when the non-destructive destination is same as the first source.

For example:

eaddl r18, r18, r25 can be encoded as addl r18, r25 using APX REX2 encoding
eaddl r2, r2, r7 can be encoded as addl r2, r7 using non-APX legacy encoding