The `MLProgramPipelineGlobals` pass crashed with a null pointer dereference
when a `CallOpInterface` operation referred to a callee symbol that could not
be resolved in the IR (e.g. an external function defined outside the module).
Instead conservatively bail out when a callee symbol cannot be resolved,
causing the pass to (preserving all loads/stores). This is consistent with
how Value-based callees are handled.
Fixes#109649
Assisted-by: Claude Code
7b744a511e