Fix duplicate job run parameters

[vfreex]

Triggering a job run from Jenkins UI or triggers defined in the job
could cause duplicate parameters. This is caused by missing checks
between the build strategy parameters and user specified parameters.

Using LinkedHashMap instread of ArrayList for parameters can
solve this issue, where the user specified parameters are able to overrides those defined in the build strategy silently.

Reproduction:
Create a BuildConfig on OpenShift with JenkinsPipelineBuildStrategy, define an environment variable NAME. Note there is a cron trigger that triggers this job every 3 minutes.

kind: "BuildConfig"
apiVersion: "v1"
metadata:
  name: "demo-pipeline"
spec:
  strategy:
    jenkinsPipelineStrategy:
      env:
      - name: "NAME"
        value: "openshift"
      jenkinsfile: |-
        pipeline {
          agent {
            kubernetes {
              cloud 'openshift'
              label "jenkins-slave-${UUID.randomUUID().toString()}"
              yaml """
              apiVersion: v1
              kind: Pod
              metadata:
                labels:
                  app: "my-jenkins-slave"
              spec:
                containers:
                - name: jnlp
                  image: docker.io/openshift/jenkins-slave-base-centos7:latest
                  tty: true
                  resources:
                    requests:
                      memory: 512Mi
                      cpu: 200m
              """
            }
          }
          triggers { cron('*/3 * * * *') }
          stages {
            stage('foo') {
              steps {
                echo "Hello, ${params.NAME}"
              }
            }
          }
        }

Then start a job run with oc start-build demo-pipeline to let Jenkins Sync plugin create a Jenkins job.
Next, start a job run from Jenkins UI, or wait for a new job run started by the cron trigger. You should see there are 2 duplicate parameters with the same name.

[vfreex]

A bug is reported to Red Hat Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1622014

[gabemontero]

/ok-to-test

[gabemontero]

/lgtm

[openshift-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: gabemontero, vfreex

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[gabemontero]

thanks @vfreex !

[gabemontero]

v 1.0.26 of the sync plugin has been initiated