test-bot: ensure cleanup is running

Closes Homebrew/homebrew#44982.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>

Library/Homebrew/cmd/test-bot.rb

@@ -746,13 +746,16 @@ module Homebrew
 
     def run
       cleanup_before
+      begin
         download
         setup
         homebrew
         formulae.each do |f|
           formula(f)
         end
+      ensure
         cleanup_after
+      end
       check_results
     end
   end
@@ -1019,9 +1022,8 @@ module Homebrew
         file.write email_subject
       end
     end
-
+  ensure
     HOMEBREW_CACHE.children.each(&:rmtree) if ARGV.include? "--clean-cache"
-
     Homebrew.failed = any_errors
   end
 end