net: work around runtime scheduler starvation on js and wasip1

net: work around runtime scheduler starvation on js and wasip1

Fixes #65177.
Updates #65178.
Updates #64321.

Change-Id: I698fd3b688c7dfbde692eb7c29cbdafc89e7ca32
Cq-Include-Trybots: luci.golang.try:gotip-js-wasm,gotip-wasip1-wasm_wasmtime,gotip-wasip1-wasm_wazero
Reviewed-on: https://go-review.googlesource.com/c/go/+/557037
Auto-Submit: Bryan Mills <bcmills@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Damien Neil <dneil@google.com>