Update macOS image and XCode version

Author: wtgodbe

.azure/pipelines/jobs/default-build.yml

@@ -106,7 +106,7 @@ jobs:
       # See https://github.com/dotnet/arcade/blob/master/Documentation/ChoosingAMachinePool.md
       pool:
         ${{ if eq(parameters.agentOs, 'macOS') }}:
-          vmImage: macOS-15
+          vmImage: macOS-13
         ${{ if eq(parameters.agentOs, 'Linux') }}:
           ${{ if eq(parameters.useHostedUbuntu, true) }}:
             vmImage: ubuntu-20.04
@@ -164,8 +164,8 @@ jobs:
         - script: df -h
           displayName: Disk size
       - ${{ if eq(parameters.agentOs, 'macOS') }}:
-        - script: sudo xcode-select -s /Applications/Xcode_16.1.0.app/Contents/Developer
-          displayName: Use XCode 16.1.0
+        - script: sudo xcode-select -s /Applications/Xcode_15.2.0.app/Contents/Developer
+          displayName: Use XCode 15.2.0
       - checkout: self
         clean: true
       - ${{ if and(eq(parameters.agentOs, 'Windows'), eq(parameters.isAzDOTestingJob, true)) }}:
@@ -320,7 +320,7 @@ jobs:
       pool:
         ${{ if eq(parameters.agentOs, 'macOS') }}:
           name: Azure Pipelines
-          image: macOS-15
+          image: macOS-13
           os: macOS
         ${{ if eq(parameters.agentOs, 'Linux') }}:
           name: $(DncEngInternalBuildPool)
@@ -382,8 +382,8 @@ jobs:
         - script: df -h
           displayName: Disk size
       - ${{ if eq(parameters.agentOs, 'macOS') }}:
-        - script: sudo xcode-select -s /Applications/Xcode_16.1.0.app/Contents/Developer
-          displayName: Use XCode 16.1.0
+        - script: sudo xcode-select -s /Applications/Xcode_15.2.0.app/Contents/Developer
+          displayName: Use XCode 15.2.0
       - checkout: self
         clean: true
       - ${{ if and(eq(parameters.agentOs, 'Windows'), eq(parameters.isAzDOTestingJob, true)) }}: