[X86] Prevent non-temporal loads from folding into instructions by blocking...

[X86] Prevent non-temporal loads from folding into instructions by blocking them in X86DAGToDAGISel::IsProfitableToFold rather than with a predicate.

Remove tryFoldVecLoad since tryFoldLoad would call IsProfitableToFold and pick up the new check.

This saves about 5K out of ~600K on the generated isel table.

llvm-svn: 344189