[BEAM-2855] implement query 12

[leiyiz]

implemented query 12, which only runs in streaming mode currently

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Post-Commit Tests Status (on master branch)

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

Pre-Commit Tests Status (on master branch)

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

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GitHub Actions Tests Status (on master branch)

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[leiyiz]

R: @y1chi
R: @pabloem

[codecov]

Codecov Report

Merging #12675 into master will decrease coverage by 0.02%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master   #12675      +/-   ##
==========================================
- Coverage   34.34%   34.32%   -0.03%     
==========================================
  Files         692      695       +3     
  Lines       81948    82234     +286     
  Branches     9263     9295      +32     
==========================================
+ Hits        28144    28225      +81     
- Misses      53381    53586     +205     
  Partials      423      423              

Impacted Files	Coverage Δ
io/gcp/bigquery_test.py	27.39% <0.00%> (-0.18%)	⬇️
runners/interactive/interactive_runner.py	30.90% <0.00%> (ø)
testing/benchmarks/nexmark/nexmark_launcher.py	0.00% <0.00%> (ø)
runners/interactive/recording_manager_test.py	28.87% <0.00%> (ø)
runners/interactive/recording_manager.py	30.57% <0.00%> (ø)
testing/benchmarks/nexmark/queries/query12.py	0.00% <0.00%> (ø)
io/gcp/bigquery.py	26.89% <0.00%> (+0.06%)	⬆️

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[y1chi]

LGTM

[pabloem]

LGTM! Thanks @leiyiz