Golang bytes: IndexByte can return -4294967295 when memory usage is above 2^31 on js/wasm [1.21 backport]

@randall77 requested issue #65571 to be considered for backport to the next 1.21 minor release.

@gopherbot please open backport issues.

This bug causes {bytes,string}.Index functions to return wrong results when used with very large arguments.

Comment From: gopherbot

Change https://go.dev/cl/598995 mentions this issue: [release-branch.go1.21] internal/bytealg: extend memchr result correctly on wasm

Comment From: gopherbot

Closed by merging CL 598995 (commit d149ce82af8d1891d5ebd5d4f968541240567c68) to release-branch.go1.21.