[X86][BtVer2] Add tests that show how ReadAfterLd is missing for some

instructions.

In the Btver2 model, there are a few InstRW overrides that don't specify a
ReadAfterLd for the register input operand.

As a result, a few AVX variants of horizontal operations and most vector logic
operations with a folded memory operand don't have a ReadAdvance info associated
to their input register operands.

llvm-svn: 328865