[mlir] Do not use pass labels in unrolled ProgressiveVectorToSCF

Do not rely on pass labels to detect if the pattern was already applied in the past (which allows for more some extra optimizations to avoid extra InsertOps and ExtractOps). Instead, check if these optimizations can be applied on-the-fly.

This also fixes a bug, where vector.insert and vector.extract ops sometimes disappeared in the middle of the pass because they get folded away, but the next application of the pattern expected them to be there.

Differential Revision: https://reviews.llvm.org/D102206