Bump IREE version pins to 3.2.0rc20250109. (#802)

See #760 for context. We want
to stay close to the latest versions while still pinning versions for
predictability. Updating version pins is currently a manual process but
we plan on automating it in the future.

We can decide how noisy we want these dependency updates to be:

* new PRs daily or less frequently
* do or don't reuse existing PRs
* merge ASAP or let them sit for multiple days

requirements-iree-pinned.txt

@@ -3,6 +3,6 @@
 # Keep these versions synced with SHORTFIN_IREE_GIT_TAG in shortfin/CMakeLists.txt
 --pre
 --find-links https://iree.dev/pip-release-links.html
-iree-base-compiler==3.1.0rc20250107
-iree-base-runtime==3.1.0rc20250107
-iree-turbine==3.1.0rc20250107
+iree-base-compiler==3.2.0rc20250109
+iree-base-runtime==3.2.0rc20250109
+iree-turbine==3.2.0rc20250109