[X86] Remove FMA3Info DenseMap. Break into sorted tables that we can binary search.

[X86] Remove FMA3Info DenseMap. Break into sorted tables that we can binary search.

I separated out the rounding and broadcast groups into their own tables because it made the ordering in the main table easier.

Further splitting of the tables might make it possible to directly index using bits from the TSFlags, but its probably not worth it right now.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@336075 91177308-0d34-0410-b5e6-96231b3b80d8