build: fix Appveyor test workflow checkout (#39137)

* build: fix Appveyor test workflow checkout

* fix: +refs/pull/num/merge -> +refs/pull/num/head

* chore: add to appveyor-woa as well

appveyor-woa.yml

@@ -51,6 +51,11 @@ environment:
       APPVEYOR_BUILD_WORKER_IMAGE: base-woa
       APPVEYOR_BUILD_WORKER_CLOUD: electronhq-woa
 
+clone_script:
+- ps: git clone -q $("--branch=" + $Env:APPVEYOR_REPO_BRANCH) $("https://github.com/" + $Env:APPVEYOR_REPO_NAME + ".git") $Env:APPVEYOR_BUILD_FOLDER
+- ps: if (!$Env:APPVEYOR_PULL_REQUEST_NUMBER) {$("git checkout -qf " + $Env:APPVEYOR_REPO_COMMIT)}
+- ps: if ($Env:APPVEYOR_PULL_REQUEST_NUMBER) {git fetch -q origin +refs/pull/$($Env:APPVEYOR_PULL_REQUEST_NUMBER)/head; git checkout -qf FETCH_HEAD}
+
 clone_folder: C:\projects\src\electron
 
 skip_branch_with_pr: true

appveyor.yml

@@ -49,6 +49,11 @@ environment:
     - job_name: Test
       job_depends_on: Build
 
+clone_script:
+- ps: git clone -q $("--branch=" + $Env:APPVEYOR_REPO_BRANCH) $("https://github.com/" + $Env:APPVEYOR_REPO_NAME + ".git") $Env:APPVEYOR_BUILD_FOLDER
+- ps: if (!$Env:APPVEYOR_PULL_REQUEST_NUMBER) {$("git checkout -qf " + $Env:APPVEYOR_REPO_COMMIT)}
+- ps: if ($Env:APPVEYOR_PULL_REQUEST_NUMBER) {git fetch -q origin +refs/pull/$($Env:APPVEYOR_PULL_REQUEST_NUMBER)/head; git checkout -qf FETCH_HEAD}
+
 clone_folder: C:\projects\src\electron
 
 skip_branch_with_pr: true