[release-v0.37.x] de-dupe order and resource dependencies

[pritidesai]

Changes

This is a manual cherry-pick of #5446.

In case of a pipeline with a huge list of redundant dependencies, the list is growing exponentially. This way of calculating the list of dependencies is causing extra delay in the validation cycle. This delay sometimes hit the webhook timeout during validation. This is one of the changes being proposed to make the validation cycle efficient and avoid unnecessary delay.

/kind bug

Submitter Checklist

As the author of this PR, please check off the items in this checklist:

• Has Docs included if any changes are user facing
• Has Tests included if any functionality added or changed
• Follows the commit message standard
• Meets the Tekton contributor standards (including
  functionality, content, code)
• Has a kind label. You can add one by adding a comment on this PR that contains /kind <type>. Valid types are bug, cleanup, design, documentation, feature, flake, misc, question, tep
• Release notes block below has been updated with any user facing changes (API changes, bug fixes, changes requiring upgrade notices or deprecation warnings)
• Release notes contains the string "action required" if the change requires additional action from users switching to the new release

Release Notes

De-dupe task dependencies - order and resource dependencies all together. It's very common to have a task with multiple when expressions referring to the same task but different results. Maintain a set of dependencies and add only a new parent.

[tekton-robot]

The following is the coverage report on the affected files.
Say /test pull-tekton-pipeline-go-coverage to re-run this coverage report

File	Old Coverage	New Coverage	Delta
pkg/apis/pipeline/v1beta1/pipeline_types.go	96.8%	96.6%	-0.2
pkg/reconciler/pipelinerun/resources/pipelinerunstate.go	97.9%	97.8%	-0.2

[abayer]

/retest

[abayer]

/approve

[tekton-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: abayer

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [abayer]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[vdemeester]

/lgtm