Merge pull request #28574 from dotnet/merges/dev15.8.x-to-dev15.9.x

Merge dev15.8.x to dev15.9.x

build/scripts/build.ps1

@@ -596,8 +596,8 @@ function Test-XUnit() {
     $dlls = $dlls | ?{ -not ($_.FullName -match ".*/ref/.*") }
 
     if ($cibuild -or $official) {
-        # Use a 50 minute timeout on CI
-        $args += " -xml -timeout:50"
+        # Use a 75 minute timeout on CI
+        $args += " -xml -timeout:75"
     }
 
     if ($procdump) {