Remove tb.ArrayOrString

[imjasonh]

This was redundant with v1beta1.NewArrayOrString

Also use v1beta1.NewArrayOrString more consistently everywhere it can be used.

Also clean up some tests for brevity/readability

#3178

git grep "tb\." goes from 3141 -> 3067 😕

/assign @pritidesai

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[imjasonh]

/kind cleanup

[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
internal/builder/v1beta1/pipeline.go	82.0%	81.8%	-0.2
internal/builder/v1beta1/task.go	75.5%	75.4%	-0.1
pkg/apis/pipeline/v1beta1/param_types.go	78.0%	87.5%	9.5
pkg/reconciler/pipelinerun/resources/resultrefresolution.go	91.9%	92.6%	0.7

[vdemeester]

/lgtm
/meow
😻

[tekton-robot]

@vdemeester:

In response to this:

/lgtm
/meow
😻

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[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
internal/builder/v1beta1/pipeline.go	82.0%	81.8%	-0.2
internal/builder/v1beta1/task.go	75.5%	75.4%	-0.1
pkg/apis/pipeline/v1beta1/param_types.go	78.0%	87.5%	9.5

[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
internal/builder/v1beta1/pipeline.go	82.0%	81.8%	-0.2
internal/builder/v1beta1/task.go	75.5%	75.4%	-0.1
pkg/apis/pipeline/v1beta1/param_types.go	78.0%	87.5%	9.5

[vdemeester]

/lgtm

[dlorenc]

/approve

[tekton-robot]

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This pull-request has been approved by: dlorenc

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