Can write "wasm" instead of js || wasi1p, since there's only two:
$ go tool dist list | grep wasm
js/wasm
wasip1/wasm
Plus, if GOOS=wasip2 is added later, we're already set.
Updates #5794
Change-Id: Ifcfb187c3775c17c9141bc721512dc4577ac4434
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>