Add pytorch_aot_simple sample Colab notebook using SHARK-Turbine. (#15166)

Progress on https://github.com/openxla/iree/issues/15117

From [SHARK-Turbine](https://github.com/nod-ai/SHARK-Turbine)'s README:
> *AOT Export*: For compiling one or more `nn.Module`s to compiled,
deployment ready artifacts. This operates via both a [simple one-shot
export
API](https://github.com/nod-ai/SHARK-Turbine/blob/main/python/shark_turbine/aot/exporter.py)
for simple models and an underlying [advanced
API](https://github.com/nod-ai/SHARK-Turbine/blob/main/python/shark_turbine/aot/compiled_module.py)
for complicated models and accessing the full features of the runtime.

This notebook shows how to use the "simple one-shot export API", with a
branch between in-session compilation using `export_output.compile()`
and export to native tools using `export_output.save_mlir()`. Some
portion of this notebook may be included as a code sample for
https://github.com/openxla/iree/issues/15114.

Preview URL for review:
https://colab.research.google.com/github/scotttodd/iree/blob/pytorch-samples-2/samples/colab/pytorch_aot_simple.ipynb

skip-ci: no-op
diff --git a/samples/colab/test_notebooks.py b/samples/colab/test_notebooks.py
index 17ca31e..d441eec 100755
--- a/samples/colab/test_notebooks.py
+++ b/samples/colab/test_notebooks.py
@@ -15,7 +15,8 @@
     # tflite_runtime requires some deps ("version `GLIBC_2.29' not found") that
     # samples.Dockerfile does not currently include.
     "tflite_text_classification.ipynb",
-    # Requires Python 3.10+ in our Docker image.
+    # PyTorch notebooks using SHARK-Turbine require Python 3.10+ in Docker.
+    "pytorch_aot_simple.ipynb",
     "pytorch_jit.ipynb",
 ]