chore(ci): add arm64ec to pull request CI

Author: nfrechette

.github/workflows/build_pull_request.yml

@@ -149,6 +149,14 @@ jobs:
         run: python3 make.py -ci -compiler vs2022 -config Release -cpu arm64 -build
       - name: Clean
         run: python3 make.py -clean_only
+      - name: Building (debug-arm64)
+        run: python3 make.py -ci -compiler vs2022 -config Debug -cpu arm64ec -build
+      - name: Clean
+        run: python3 make.py -clean_only
+      - name: Building (release-arm64)
+        run: python3 make.py -ci -compiler vs2022 -config Release -cpu arm64ec -build
+      - name: Clean
+        run: python3 make.py -clean_only
       - name: Building (debug-x64) with Clang
         run: python3 make.py -ci -compiler vs2022-clang -config Debug -cpu x64 -build
       - name: Running unit tests (debug-x64) with Clang