patch: runtime: fix value of ENOSYS on mips from 38 to 89

[nickkhyl]

I'd like to cherry-pick the changes from https://go-review.googlesource.com/c/go/+/747664 into our Go tree before the 1.26 backport lands upstream to fix tailscale/tailscale#19039 (golang#77730).

runtime: fix value of ENOSYS on mips from 38 to 89

Fixes #77730

Change-Id: I8b68b2d4353344e70f970d48a2d50c1a3bd7f273
Reviewed-on: https://go-review.googlesource.com/c/go/+/747664
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Rongrong <rongrong-for-oss@oss.cipunited.com>
Reviewed-by: Michael Pratt <mpratt@google.com>

/cc @tailscale/tooling