[X86][BtVer2] Fix the number of micro opcodes for a bunch of YMM instructions.

The Jaguar backend natively supports 128-bit data types. Operations on YMM
registers are split into two COPs (complex operations). Each COP consumes a slot
in the dispatch group, and in the reorder buffer.

The scheduling model for Jaguar should mark those instructions as `let
NumMicroOps = 2`.

This was found when testing AVX code for BtVer2 using llvm-mca.

llvm-svn: 328694