http2: emit error on canceled streams when aborted event is not emitted

[mcollina]

When a client HTTP/2 stream's writable side is already ended (e.g. GET requests), receiving RST code 8 (NGHTTP2_CANCEL) emitted neither the aborted nor the error event, causing the stream to close silently.

The fix only skips error generation for NGHTTP2_CANCEL when the aborted event was actually emitted.

Fixes: #56627

[nodejs-github-bot]

Review requested:

• @nodejs/http2
• @nodejs/net

[codecov]

Codecov Report

❌ Patch coverage is 71.42857% with 10 lines in your changes missing coverage. Please review.
✅ Project coverage is 89.65%. Comparing base (58a8e1d) to head (e2f40e3).
⚠️ Report is 127 commits behind head on main.

Files with missing lines	Patch %	Lines
lib/internal/http2/core.js	71.42%	10 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #62923      +/-   ##
==========================================
- Coverage   89.69%   89.65%   -0.04%     
==========================================
  Files         706      707       +1     
  Lines      218222   219538    +1316     
  Branches    41768    42103     +335     
==========================================
+ Hits       195731   196833    +1102     
- Misses      14411    14599     +188     
- Partials     8080     8106      +26     

Files with missing lines	Coverage Δ
lib/internal/http2/core.js	95.01% <71.42%> (-0.23%)	⬇️

... and 80 files with indirect coverage changes

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