This PR moves the patterns that unroll vector.to_elements and
vector.from_elements into the file with other vector unrolling
operations. This PR also adds these unrolling patterns into the
`populateVectorUnrollPatterns`. And renames
`populateVectorToElementsLoweringPatterns`
`populateVectorFromElementsLoweringPatterns` to
`populateVectorToElementsUnrollPatterns`
`populateVectorFromElementsUnrollPatterns`.