stream: align `Readable.toWeb` termination with eos #6940

Job	Run time
Build slim tarball	1m 42s
aarch64-darwin: with shared libraries	27m 21s
x86_64-linux: with shared libraries	27m 52s
aarch64-linux: Cache V8 build	22s
x86_64-darwin: with shared libraries	52m 49s
aarch64-linux: with shared openssl-3.0.19	25m 16s
aarch64-linux: with shared openssl-1.1.1w	23m 49s
aarch64-linux: with shared boringssl-0.20260413.0	23m 49s
aarch64-linux: with shared openssl-4.0.0	24m 24s
aarch64-linux: with shared openssl-3.6.1	23m 45s
aarch64-linux: with shared openssl-3.5.5	24m 10s
	4h 15m 19s

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