[Mosaic GPU] Add a bank-conflict checker to tiled transfer + transfer planner

Instead of only allowing a fixed set of layouts that we've hand verified as
bank-conflict free, we now simulate the transactions performed within each
warp and verify that no bank conflicts happen. If we detect that the simple
schedule does not work out, we attempt to partition the threads in a warp
into two groups and stagger the transfers in a way that lets us avoid conflicts.

This allows us to match the hand-designed transfer schedule I wrote for 32-bit
types, and even generalizes it to more cases automatically (e.g. swizzle=32).