Add build_runtime_windows CI job. (#11012)

Progress on #11009

Tested here:
https://github.com/ScottTodd/iree/actions/runs/3380820232/jobs/5614038219

Post-submit only for now, so we can monitor it. I saw one build hang in
the "Configuring MSVC" step:
https://github.com/ScottTodd/iree/actions/runs/3380762369/jobs/5613916852

.github/workflows/ci.yml

@@ -284,6 +284,22 @@ jobs:
           name: "${{ env.BUILD_DIR }}.tar"
           path: "${{ env.BUILD_DIR }}.tar"
 
+  build_runtime_windows:
+    needs: setup
+    if: needs.setup.outputs.should-run == 'true' && needs.setup.outputs.ci-stage == 'postsubmit'
+    runs-on: windows-2022
+    env:
+      BUILD_DIR: build-runtime
+    steps:
+      - name: "Checking out repository"
+        uses: actions/checkout@7884fcad6b5d53d10323aee724dc68d8b9096a2e # v2
+      - name: "Checking out runtime submodules"
+        run: bash ./build_tools/scripts/git/update_runtime_submodules.sh
+      - name: "Configuring MSVC"
+        uses: ilammy/msvc-dev-cmd@7315a94840631165970262a99c72cfb48a65d25d # v1.12.0
+      - name: "Building runtime"
+        run: bash ./build_tools/cmake/build_runtime.sh "${BUILD_DIR}"
+
   test_runtime:
     needs: [setup, build_runtime]
     if: needs.setup.outputs.should-run == 'true'
@@ -758,6 +774,7 @@ jobs:
 
       # Subsets
       - build_runtime
+      - build_runtime_windows
       - test_runtime
 
       # Tensorflow

build_tools/scripts/git/update_runtime_submodules.sh

@@ -12,6 +12,7 @@ set -xeuo pipefail
 
 SCRIPT_DIR="$(dirname -- "$( readlink -f -- "$0"; )")"
 
-readarray -t RUNTIME_SUBMODULES < "${SCRIPT_DIR}/runtime_submodules.txt"
+# Read lines from runtime_submodules.txt, stripping \r characters on Windows.
+readarray -t RUNTIME_SUBMODULES < <(cat build_tools/scripts/git/runtime_submodules.txt | tr -d '\r')
 
-git submodule sync && git submodule update --init ${RUNTIME_SUBMODULES[@]}
+git submodule sync && git submodule update --init --jobs 8 --depth 1 ${RUNTIME_SUBMODULES[@]}