Adding Models to Test Matrix for Zephyr CI Test (pytorch#13193)

### Summary
Previously, only the example Add model was included in the matrix of
models that the Zephyr CI job tests. The Add model isn't very
representative of real-world models, and may give a false sense of
security on the functionality of incorporating ExecuTorch with Zephyr.
This PR adds the simple `Softmax` and `Mobilenet V2` models to the test
matrix. While the `Softmax` model is like the `Add` model (a toy
example), `Mobilenet V2` includes using an image from the `imagenet`
validation set, and verifies that the top predicted label matches
expectation (i.e. predict "Samoyed" as best label). All three of these
tests show example of this flow can be extend further for other models.
Thus this PR integrates these test to ensure compatibility between
ExecuTorch and Zephyr is maintained.

### Test plan
Verified that these models work with the Zephyr ecosystem manually in a
separate docker image.

Author: BujSet

.github/workflows/trunk.yml

@@ -60,7 +60,7 @@ jobs:
     uses: pytorch/test-infra/.github/workflows/linux_job.yml@main
     strategy:
       matrix:
-        model: [add]
+        model: [add, softmax, mv2]
       fail-fast: false
     with:
       runner: linux.2xlarge
@@ -72,6 +72,16 @@ jobs:
         MODEL_NAME=${{ matrix.model }}
         CONDA_ENV=$(conda env list --json | jq -r ".envs | .[-1]")
         conda activate "${CONDA_ENV}"
+        if [[ ${{ matrix.model}} == "add" ]]; then
+          SIM_LIMIT_SEC=60
+        elif [[ ${{ matrix.model}} == "softmax" ]]; then
+          SIM_LIMIT_SEC=60
+        elif [[ ${{ matrix.model}} == "mv2" ]]; then
+          SIM_LIMIT_SEC=5000
+        else
+          echo "Failed unsupported model selection ${{ matrix.model }}"
+          exit 1
+        fi
 
         source .ci/scripts/utils.sh
         source .ci/scripts/zephyr-utils.sh
@@ -118,24 +128,22 @@ jobs:
             -C mps3_board.uart0.out_file='sim.out'  \
             -C cpu0.CFGITCMSZ=15 \
             -C cpu0.CFGDTCMSZ=15 \
-            --simlimit 120
+            --simlimit ${SIM_LIMIT_SEC}
 
         # Disable exit on error
         set +e
         # Report failure if any of the ouptut verification checks fail
-        # store 0 if found (failure), 1 if not (success)
         grep -qF "ERROR" sim.out
-        exit_status=$?
+        exit_status=$? #store 0 if found (failure), 1 if not (success)
         if [[ "$exit_status" -eq "0" ]]; then
             cat sim.out
             set -e
             exit 1
         fi
 
         # Report fail if simulation does not complete successfully
-        # store 0 if found (success), 1 if not (failure)
         grep -qF "SUCCESS: Program complete, exiting." sim.out
-        exit_status=$?
+        exit_status=$? #store 0 if found (success), 1 if not (failure)
         if [[ "$exit_status" -eq "1" ]]; then
             cat sim.out
             set -e