stream: minor stream/iter implementation edits

[Renegade334]

Changes:

• Splits out arrayBufferViewToUint8Array() from primitiveToUint8Array(), as transform processing makes extensive use of this utility but exclusively to handle ABVs, which allows these cases to shortcut the other chunk typechecks.
• Uses flattenTransformYieldSync() to flatten sync iterables in async pipelines. The spec text is not entirely clear how these cases should be flattened, but extrapolated from how sync iterables are handled in async from(), they should be handled the same as if they were being flattened in a sync pipeline, ie. they must not yield nested async iterators.
• Add a fast path to concatBytes() for cloning a single chunk, by passing the chunk directly to the Uint8Array constructor.
• Replaces the dependency on Buffer.concat() in concatBytes() with a thin inline concatenation implementation.
• Uses yield* in withFlushAsync(): the operator preferentially async-iterates its target within an async generator, without the need to unwrap the iteration.
• Adds some remaining array prototype primordials for consistency.

Pseudo-tested by running the new-stream samples, which shows no changes between this PR and main.

[nodejs-github-bot]

Review requested:

• @nodejs/streams

[codecov]

Codecov Report

❌ Patch coverage is 88.88889% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 89.68%. Comparing base (6df4f7b) to head (0b28453).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
lib/internal/streams/iter/pull.js	60.00%	6 Missing ⚠️
lib/internal/streams/iter/classic.js	83.33%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #63132   +/-   ##
=======================================
  Coverage   89.67%   89.68%           
=======================================
  Files         712      712           
  Lines      221251   221267   +16     
  Branches    42391    42394    +3     
=======================================
+ Hits       198405   198438   +33     
+ Misses      14669    14646   -23     
- Partials     8177     8183    +6     

Files with missing lines	Coverage Δ
lib/internal/streams/iter/consumers.js	96.56% <100.00%> (+<0.01%)	⬆️
lib/internal/streams/iter/from.js	88.81% <100.00%> (+0.09%)	⬆️
lib/internal/streams/iter/utils.js	100.00% <100.00%> (ø)
lib/internal/streams/iter/classic.js	89.34% <83.33%> (+0.01%)	⬆️
lib/internal/streams/iter/pull.js	85.16% <60.00%> (ø)

... and 38 files with indirect coverage changes

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