Temporarily pin IREE release

Unblock the breakage from https://github.com/openxla/iree/issues/16026

Bug: 318408783
Change-Id: I00c3dbc08871031253639c92fef0b3fa126b6114
diff --git a/manifest.xml b/manifest.xml
index 201ffdd..9231376 100644
--- a/manifest.xml
+++ b/manifest.xml
@@ -57,7 +57,8 @@
   <!-- END cantrip components -->
 
   <!-- BEGIN ML toolchain-->
-  <project revision="latest-snapshot" name="3p/openxla/iree" path="toolchain/iree" />
+  <!-- TODO(b/318408783): unpin the IREE release -->
+  <project revision="4592b8f5a95f8f3a6da574df83b81600169947a5" name="3p/openxla/iree" path="toolchain/iree" />
   <project name="sw/vec_iree"                     path="sw/vec_iree" />
   <project name="ml-models-public"                path="ml/ml-models-public" />
   <!-- END ML toolchain -->