Revert "Suppress cleanupcode on linux"

This reverts commit ee77e53.

Author: bkoelman

Build.ps1

@@ -38,7 +38,7 @@ function RunInspectCode {
 function RunCleanupCode {
     # When running in cibuild for a pull request, this reformats only the files changed in the PR and fails if the reformat produces changes.
 
-    if ($env:APPVEYOR_PULL_REQUEST_HEAD_COMMIT -and $IsWindows) {
+    if ($env:APPVEYOR_PULL_REQUEST_HEAD_COMMIT) {
         # In the past, we used $env:APPVEYOR_PULL_REQUEST_HEAD_COMMIT for the merge commit hash. That is the pinned hash at the time the build is enqueued.
         # When a force-push happens after that, while the build hasn't yet started, this hash becomes invalid during the build, resulting in a lookup error.
         # To prevent failing the build for unobvious reasons we use HEAD, which is always a detached head (the PR merge result).