4.x: Unit test lambdaification 4 of N

[akarnokd]

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

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: 4.676 bits/char
Verdict: ✅ Mid-4 beauty detected (thoughtful human code!)

Changed files entropy:

src/test/java/io/reactivex/rxjava4/completable/CompletableTest.java: 4.620
src/test/java/io/reactivex/rxjava4/core/TransformerTest.java: 4.737
src/test/java/io/reactivex/rxjava4/core/XFlatMapTest.java: 4.345
src/test/java/io/reactivex/rxjava4/flowable/FlowableBackpressureTests.java: 4.593
src/test/java/io/reactivex/rxjava4/flowable/FlowableCollectTest.java: 4.469
src/test/java/io/reactivex/rxjava4/flowable/FlowableCombineLatestTests.java: 5.004
src/test/java/io/reactivex/rxjava4/flowable/FlowableConcatTests.java: 4.818
src/test/java/io/reactivex/rxjava4/flowable/FlowableConversionTest.java: 4.394
src/test/java/io/reactivex/rxjava4/flowable/FlowableCovarianceTest.java: 4.818
src/test/java/io/reactivex/rxjava4/flowable/FlowableDoAfterNextTest.java: 4.837
src/test/java/io/reactivex/rxjava4/flowable/FlowableDoOnTest.java: 4.789
src/test/java/io/reactivex/rxjava4/flowable/FlowableErrorHandlingTests.java: 4.683

✅ 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 98.79%. Comparing base (8dad743) to head (c60aa6d).

Additional details and impacted files

@@             Coverage Diff              @@
##                4.x    #8140      +/-   ##
============================================
+ Coverage     98.77%   98.79%   +0.02%     
- Complexity     6871     6874       +3     
============================================
  Files           769      769              
  Lines         48659    48659              
  Branches       6516     6516              
============================================
+ Hits          48061    48074      +13     
+ Misses          458      452       -6     
+ Partials        140      133       -7     

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