[BEAM-12273] Cherrypick #14715 to release 2.30.0: Support both iterable and multimap materialization in Twister2 runner

[kennknowles]

Before this, the side input functionality is broken in twister2 runner on the 2.30.0 release branch.

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ValidatesRunner compliance status (on master branch)

Lang	ULR	Dataflow	Flink	Samza	Spark	Twister2
Go	---			---		---
Java
Python	---			---		---
XLang				---		---

Examples testing status on various runners

Lang	ULR	Dataflow	Flink	Samza	Spark	Twister2
Go	---	---	---	---	---	---	---
Java	---		---	---	---	---	---
Python	---	---	---	---	---	---	---
XLang	---	---	---	---	---	---	---

Post-Commit SDK/Transform Integration Tests Status (on master branch)

Go	Java	Python

Pre-Commit Tests Status (on master branch)

---	Java	Python	Go	Website	Whitespace	Typescript
Non-portable
Portable	---			---	---	---

See .test-infra/jenkins/README for trigger phrase, status and link of all Jenkins jobs.

GitHub Actions Tests Status (on master branch)

See CI.md for more information about GitHub Actions CI.

[kennknowles]

run twister2 validatesrunner

[codecov]

Codecov Report

Merging #14725 (0176b9d) into release-2.30.0 (154c4b5) will not change coverage.
The diff coverage is n/a.

@@               Coverage Diff               @@
##           release-2.30.0   #14725   +/-   ##
===============================================
  Coverage           83.64%   83.64%           
===============================================
  Files                 440      440           
  Lines               58983    58983           
===============================================
  Hits                49338    49338           
  Misses               9645     9645           

Impacted Files	Coverage Δ
...sdks/python/apache_beam/utils/interactive_utils.py	87.80% <0.00%> (-7.32%)	⬇️
...hon/apache_beam/runners/direct/test_stream_impl.py	91.79% <0.00%> (-2.24%)	⬇️
...hon/apache_beam/runners/worker/bundle_processor.py	93.74% <0.00%> (ø)
...ks/python/apache_beam/runners/worker/data_plane.py	91.31% <0.00%> (+1.79%)	⬆️

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[ihji]

Thanks!