Add gcc-serial GitHub Actions job using AT2 platform

Add gcc-serial GitHub Actions job to the AT2 workflow file. This job
will only run on GitHub Runners with the label `gcc-8.3.0_serial`
specified which have an existing gcc-serial container environment ready
for testing.

TODO: lots of repeated lines with gcc-openmpi job, once Framework
has more AT2 jobs added, we will look into condensing the lines using
GitHub Composite Actions.

Story ref: TRILFRAME-629

Author: achauphan

.github/workflows/AT2.yml

@@ -74,3 +74,62 @@ jobs:
       - name: ctest
         working-directory: /home/Trilinos/build
         run: bash -l -c "ctest -j16"
+
+  gcc830-serial-EXPERIMENTAL:
+    runs-on: [self-hosted, gcc-8.3.0_serial]
+    if: ${{ github.event.action == 'synchronize' || github.event.action == 'opened' || github.event.review.state == 'APPROVED' }}
+    steps:
+      - name: env
+        env:
+          GITHUB_CONTEXT: ${{ toJson(github) }}
+        run: |
+          env
+      - name: module list
+        shell: bash
+        run: |
+          bash -l -c "module list"
+          printenv PATH
+      - name: Cancel Previous Runs
+        uses: styfle/cancel-workflow-action@85880fa0301c86cca9da44039ee3bb12d3bedbfa # 0.12.1
+        with:
+          access_token: ${{ github.token }}
+      - name: make dirs
+        working-directory: /
+        run: |
+          mkdir -p /home/Trilinos/src/Trilinos
+          mkdir -p /home/Trilinos/build
+      - name: Clone trilinos
+        uses: actions/checkout@9bb56186c3b09b4f86b1c65136769dd318469633 # v4.1.2
+        with:
+          fetch-depth: 0
+      - name: Repo status
+        run: |
+          git fetch --all
+          pwd
+          ls -lhat
+          git status
+          git branch -vv
+          git branch -a
+      - name: get dependencies
+        working-directory: ./packages/framework
+        run: |
+          bash -l -c "./get_dependencies.sh --container"
+      - name: Generate PR cmake fragment
+        working-directory: /home/Trilinos/build
+        run: |
+          bash -l -c "source ${GITHUB_WORKSPACE}/packages/framework/GenConfig/gen-config.sh rhel8_gcc-serial_release-debug_shared_no-kokkos-arch_no-asan_no-complex_no-fpic_no-mpi_no-pt_no-rdc_no-uvm_deprecated-on_no-package-enables --force --cmake-fragment PR-configuration.cmake ${GITHUB_WORKSPACE}"
+      - name: Generate enable packages cmake fragment
+        working-directory: /home/Trilinos/build
+        run: |
+          bash -l -c "TRILINOS_DIR=${GITHUB_WORKSPACE} ${GITHUB_WORKSPACE}/commonTools/framework/get-changed-trilinos-packages.sh HEAD origin/develop package-enables.cmake ctest-labels.cmake" || bash -l -c "cat TribitsDumpDepsXmlScript.log"
+      - name: configure trilinos
+        working-directory: /home/Trilinos/build
+        run: |
+          bash -l -c "cmake -C PR-configuration.cmake -C package-enables.cmake ${GITHUB_WORKSPACE}"
+      - name: build trilinos
+        working-directory: /home/Trilinos/build
+        run: bash -l -c "ninja -j16"
+      - name: ctest
+        working-directory: /home/Trilinos/build
+        run: bash -l -c "ctest -j16"
+