[xla:gpu][NFC] Misc fixes to DynamicAddressComputationFusion
[xla:gpu][NFC] Misc fixes to DynamicAddressComputationFusion

FUTURE_COPYBARA_INTEGRATE_REVIEW=https://github.com/openxla/xla/pull/10536 from philipphack:u_layer_size1_xla 14075f1714dcfec83efe13b8903a34caa4b39c01
