RFR: 2016: CSRIssueBot shouldn't force CheckWorkItem to run

[Zhao Song]

Currently, all the CheckWorkItems triggered by CSRIssueBot are having some privilege, these checkWorkItems could bypass the checksum check and force the update of the PR. Even when a user add a comment to the CSR issue, it will force the bot re-evaluate the  associated PR. This is bad and we don't have choice when implementing this.

Now we have introduced issuePRMap in SKARA-1912, so we could fix the above issue.  When creating the checkWorkItem in the CSRIssueWorkItem, we could look in the IssuePRmap. If the CSR issue is not associated with the pr, then we should force the update, otherwise we don't need to force the update.

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Commit messages:
 - SKARA-2016

Changes: https://git.openjdk.org/skara/pull/1586/files
 Webrev: https://webrevs.openjdk.org/?repo=skara&pr=1586&range=00
  Issue: https://bugs.openjdk.org/browse/SKARA-2016
  Stats: 8 lines in 3 files changed: 4 ins; 1 del; 3 mod
  Patch: https://git.openjdk.org/skara/pull/1586.diff
  Fetch: git fetch https://git.openjdk.org/skara.git pull/1586/head:pull/1586

PR: https://git.openjdk.org/skara/pull/1586