[X86] Add test case to demonstrate that we don't allow masks wider than 6 bits...

[X86] Add test case to demonstrate that we don't allow masks wider than 6 bits in the (shift x, (and y, mask)) patterns for the 64-bit memory form.

We allow wider than 5 bits in the 16 and 32 bit store forms. And we allow wider than 6 bits on the 64-bit regsiter form.:w

I'm assuming this was a mistake made back in r148024.

llvm-svn: 308656