Truncate exit codes larger than 32767

What does this MR do and why?

Truncate/wraparound exit codes larger than 255

We have some (window) runners that return any exit code Other runners will only return 0..255 exit codes

This change will truncate exit codes greater than what ci_builds_metadata can handle (smallint - 32767)

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Before	After

How to set up and validate locally

Not easy to test fully locally, using mac/linux runners will return an exit code of 255 or less. This is using both script: - exit 500 on gitlab ci_yml as well as trigging bash/ruby scripts to exit.

But it's easy to test the method directly via build.drop_with_exit_code!(:script_failure, 500)

Related to #456982 (closed)

app/models/commit_status.rb

@@ -197,7 +197,11 @@ class CommitStatus < Ci::ApplicationRecord
 
       commit_status.failure_reason = reason.failure_reason_enum
       commit_status.allow_failure = true if reason.force_allow_failure?
-      commit_status.exit_code = reason.exit_code if Feature.enabled?(:ci_retry_on_exit_codes, Feature.current_request)
+      # Windows exit codes can reach a max value of 32-bit unsigned integer
+      # We only allow a smallint for exit_code in the db, hence the added limit of 32767
+      if reason.exit_code && Feature.enabled?(:ci_retry_on_exit_codes, Feature.current_request)
+        commit_status.exit_code = reason.exit_code % 32768
+      end
     end
 
     before_transition [:skipped, :manual] => :created do |commit_status, transition|