stream: corrections to source normalization

[Renegade334]

• Arrays, as special cases of sync iterables, have lower precedence than async iterables (and protocol objects) in async normalization operations.
• Sync iterables should be normalized synchronously in async normalization operations, ie. they may not contain nested async iterables (continuation of stream: minor stream/iter implementation edits #63132).
• Similarly, sync toStreamables should not be allowed to return async sources.
• No explicit rejection is required for async patterns in fromSync(); doing so may exclude objects with both sync and async functionality (eg. objects with both [Symbol.iterator] and [Symbol.asyncIterator] properties). The spec text seems to suggest that objects with a valid sync pattern should be accepted here even if they also have an async pattern, but could do with some clarity.
• In from(), normalise the object returned by toAsyncStreamable directly, not the return value of its Symbol.asyncIterator method: firstly, the async iterator returned by the Symbol.asyncIterator method is not itself obliged to have a Symbol.asyncIterator method, and secondly, the result could in theory be any valid from() source, not just an async iterable.
• Use isUint8ArrayBatch for the from()/fromSync() fast paths.

Note that as things stand, some of the from() cases throw validation errors synchronously (eg. fromSync({ [toStreamable]() {} })) whereas the majority only throw validation errors at the point of iteration. AFAICT, the latter behaviour is what is compliant with the spec, but I haven't touched these for now.

[nodejs-github-bot]

Review requested:

• @nodejs/streams

[codecov]

Codecov Report

❌ Patch coverage is 81.19658% with 22 lines in your changes missing coverage. Please review.
✅ Project coverage is 90.03%. Comparing base (3b19867) to head (5da7742).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
lib/internal/streams/iter/from.js	81.19%	22 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #63416      +/-   ##
==========================================
- Coverage   91.68%   90.03%   -1.65%     
==========================================
  Files         361      714     +353     
  Lines      156230   225741   +69511     
  Branches    24021    42710   +18689     
==========================================
+ Hits       143232   203242   +60010     
- Misses      12729    14298    +1569     
- Partials      269     8201    +7932     

Files with missing lines	Coverage Δ
lib/internal/streams/iter/from.js	81.47% <81.19%> (-5.36%)	⬇️

... and 476 files with indirect coverage changes

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