ATS crashes when using txn_box and client sends duplicate header.

[djcarlin]

This txn_box config checks if HTTP method is not PURGE, and then adds a response header depending on the value of Origin client request header.

The problem I am having is that ATS 9.1 crashes if a misbehaving client sends two Origin headers. The values of the two Origin headers doesn't seem to matter.

Using txn_box 0.4.2

- with: [ua-req-method, ua-req-field<Origin>]
  select:
  - as-tuple:
    - none-of:
      - match<nc>: "purge"
    - any-of:
      - tld: "foo.net"
      - tld: "foo-inc.com"
      - tld: "fooinc.com"
      - tld: "foo.com"
      - tld: "foo.com.nz"
    do:
    - debug: "MATCH: Origin {ua-req-field<Origin>} using method {ua-req-method}"
    - when: proxy-rsp
      do:
      - proxy-rsp-field<Access-Control-Allow-Origin>: ua-req-field<Origin>
  - otherwise:
    do:
    - debug: "NOT MATCH: Origin {ua-req-field<Origin>} using method {ua-req-method}"
    - when: proxy-rsp
      do:
      - proxy-rsp-field<Access-Control-Allow-Origin>: "*"