Change nightly azcore test to autorest (#3705)

Since the new azcore backend is now the default, we want to run a
nightly test of the legacy Autorest backend that can still be used.

.github/workflows/azcore-scheduled.yml → .github/workflows/autorest-scheduled.yml

@@ -1,4 +1,6 @@
-name: azcore-scheduled
+# This workflow runs the standard (full) CI test suite once a day or on demand,
+# using the legacy autorest backend.
+name: autorest-scheduled
 
 on:
   schedule:
@@ -19,4 +21,4 @@ jobs:
       version: ${{ needs.version.outputs.version }}
       short_test: false
       retention_days: 7
-      use_azcore: true
+      use_azcore: false

.github/workflows/build-test.yml

@@ -25,7 +25,7 @@ on:
       use_azcore:
         type: boolean
         description: Whether to use the newer azcore+azidentity backend for REST and auth, or the older autorest
-        default: false
+        default: true
 
 env:
   GITHUB_TOKEN: ${{ secrets.PULUMI_BOT_TOKEN }}