[SDXL] Regression in throughput for MLPerf Inference on IREE-3.4.0rc20250425

[monorimet]

A regression in throughput performance was observed when bumping the IREE runtime versioned used for the shortfin runtime build:

iree 3.4.0rc20250424 (artifacts from 3.6.0): Samples per second: 14.7771

iree 3.4.0rc20250425 (artifacts from 3.6.0): Samples per second: 12.9066

Needs to be root caused and issue filed in upstream IREE.