stream: simplify `readableStreamFromIterable` #5592

Job	Run time
Build slim tarball	2m 10s
x86_64-darwin: with shared libraries	31m 49s
aarch64-darwin: with shared libraries	17m 54s
x86_64-linux: with shared libraries	23m 18s
aarch64-linux: with shared libraries	20m 44s
	1h 35m 55s

Provide feedback