Audit vector-transfer-collapse-inner-most-dims.mlir (scalable vectors)

[banach-space]

Audit vector-transfer-collapse-inner-most-dims.mlir (and the corresponding patterns) and add tests for scalable vectors.

Patches:

• [mlir][vector] Update tests for collapse 6/n (nfc) #98902
• [mlir][vector] Update tests for collapse 5/n (nfc) #96227
• [mlir][vector] Restrict DropInnerMostUnitDimsTransfer{Read|Write} #96218
• [mlir][vector] Update tests for collapse 4/n (nfc) #96214
• [mlir][vector] Update tests for collapse 3/n (nfc) #94906
• [mlir][vector] Update tests for collapse 1/n (nfc) #94490
• [mlir][vector] Update tests for collapse 2/n (nfc) #94604
• [mlir][vector] Restrict DropInnerMostUnitDimsTransferRead #94904
• [mlir][test] Add comments in a test (nfc) #99810