4.x: Unit test lambdaification 22 of N

[akarnokd]

Will go over the unit tests in ASCII order of the classpath and classes.

ℹ️ Removed the **NullTests because the ParamValidationCheckerTest does that for all classes for some time now.

IntelliJ: Inspect -> RedundantCast, Inspect -> Anonymous type can be replaced by lambda
Search regexp: new\s+\w+(?:\s*<(?:[\s\w<>(\[\])?,.?]|\s*<[\s\w<>(\[\])?,.?]*>)*>)?\s*\([^)]*\)\s*\{

/* NFI */ = Not Functional Interface so break the regexp pattern

If you complain instead of proposing a PR about "why not convert to method references" you'll be banned.

Related: #8080

[github-actions]

🐷 TruffleHog + Entropy Beauty Scan

Average entropy of changed code: 4.738 bits/char
Verdict: ⚠️ Consider review — entropy outside sweet spot

Changed files entropy:

src/jmh/java/io/reactivex/rxjava4/xmapz/ObservableConcatMapCompletablePerf.java: 5.091
src/jmh/java/io/reactivex/rxjava4/xmapz/ObservableConcatMapMaybePerf.java: 5.103
src/jmh/java/io/reactivex/rxjava4/xmapz/ObservableConcatMapSinglePerf.java: 5.099
src/jmh/java/io/reactivex/rxjava4/xmapz/ObservableFlatMapCompletablePerf.java: 5.096
src/jmh/java/io/reactivex/rxjava4/xmapz/ObservableFlatMapMaybePerf.java: 5.109
src/jmh/java/io/reactivex/rxjava4/xmapz/ObservableFlatMapSinglePerf.java: 5.104
src/test/java/io/reactivex/rxjava4/internal/operators/mixed/ObservableConcatMapCompletableTest.java: 4.565
src/test/java/io/reactivex/rxjava4/internal/operators/mixed/ObservableConcatMapMaybeTest.java: 4.649
src/test/java/io/reactivex/rxjava4/internal/operators/mixed/ObservableConcatMapSingleTest.java: 4.648
src/test/java/io/reactivex/rxjava4/internal/operators/observable/ObservableAllTest.java: 4.675
src/test/java/io/reactivex/rxjava4/internal/operators/observable/ObservableAmbTest.java: 4.715
src/test/java/io/reactivex/rxjava4/internal/operators/observable/ObservableAnyTest.java: 4.707
src/test/java/io/reactivex/rxjava4/internal/operators/observable/ObservableBlockingTest.java: 4.721
src/test/java/io/reactivex/rxjava4/internal/operators/observable/ObservableBufferTest.java: 4.700
src/test/java/io/reactivex/rxjava4/internal/operators/observable/ObservableBufferUntilSubscriberTest.java: 4.494
src/test/java/io/reactivex/rxjava4/internal/operators/observable/ObservableCacheTest.java: 4.737
src/test/java/io/reactivex/rxjava4/internal/operators/observable/ObservableCollectTest.java: 4.655
src/test/java/io/reactivex/rxjava4/internal/operators/observable/ObservableCombineLatestTest.java: 4.679
src/test/java/io/reactivex/rxjava4/internal/operators/observable/ObservableConcatMapCompletableTest.java: 4.558
src/test/java/io/reactivex/rxjava4/internal/operators/observable/ObservableConcatMapEagerTest.java: 4.706

✅ No secrets or suspicious high-entropy strings found.

Mid-4 beauty heuristic in action — powered by our entropy chats! 😊

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.27%. Comparing base (e8e1c4e) to head (a2ef373).
⚠️ Report is 1 commits behind head on 4.x.

Additional details and impacted files

@@             Coverage Diff              @@
##                4.x    #8164      +/-   ##
============================================
- Coverage     98.73%   98.27%   -0.46%     
+ Complexity     6939     6930       -9     
============================================
  Files           773      773              
  Lines         48994    48994              
  Branches       6586     6586              
============================================
- Hits          48375    48151     -224     
- Misses          448      637     +189     
- Partials        171      206      +35     

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