[XLA:GPU] Renaming AddressComputationFusionRewriter to DynamicSliceFusionRewriter
[XLA:GPU] Renaming AddressComputationFusionRewriter to DynamicSliceFusionRewriter

"AddressComputation" is confusing, it simply fuses dynamic slice (and dynamic update slice) into other thunks via buffer assignment tricks

Reverts 58a97840542bac9be1aeae91d7ee7c12ee321d71
