[CPU] Big vector is generated and unrolled without warning/erroring

[Han-Chung Wang]

There are some ops (e.g., iree_linalg_ext.attention op) that do not have well support wrt tiling. It ends up with big vectors. They are fully unrolled during codegen, which leads to looooooong compilation time and huge artifacts. This is definitely a bug, and we should stop the compilation in the case. The action item is to add a pass to check if there are big vectors or not, like what we've done for stack allocation check.