[v8.x fix] - stream: fix end not being called when reading some base64 files

[marcosc90]

This fixes 'end' not being called when reading base64 files
with highWaterMark equal to: file length - 1,
and fixes 'data' not being called on some edge cases
when highWaterMark was lower than file length.

Fixes: #19862

This issue is still present in v6.x & v9.x so if everything is ok, I'll submit changes for those versions too.

Going through master history, the same line of code was changed in this commit

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• tests and/or benchmarks are included
• documentation is changed or added
• commit message follows commit guidelines

[mscdex]

I think we should instead look at backporting whichever commit(s) fixed this particular issue in master rather than pushing some new changes to one particular branch.

[addaleax]

@nodejs/streams – I can’t tell whether this might be breaking or not

[mcollina]

I think this is breaking. Unfortunately the full fix in #17979, which is semver-major for good reasons. We might want to backport that if we need to fix is needed.

[marcosc90]

Backporting those commits it's not something I would be comfortable with, since I'm not very familiar with the codebase yet. But I would be willing to add some better tests to master to prevent that bug from occurring again.

[mcollina]

@marcosc90 go for it. We definitely need better testing on streams.

[MylesBorins]

I'm closing this based on the above comments