[release-branch.go1.21] runtime/internal: switch GOWASIRUNTIME default

CL 513235 switched the default wasip1 runtime in the misc/wasm
executable script, but it missed this use of the GOWASIRUNTIME
environment variable. Update this instance to make the default runtime
choice consistent.

Change-Id: Iff7f96231422747a38d65d13a940f6e9d04d835d
Reviewed-on: https://go-review.googlesource.com/c/go/+/515116
Reviewed-by: David Chase <[email protected]>
Reviewed-by: Dmitri Shuralyov <[email protected]>
Auto-Submit: Johan Brandhorst-Satzkorn <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Reviewed-by: Dmitri Shuralyov <[email protected]>
Run-TryBot: Johan Brandhorst-Satzkorn <[email protected]>

Author: johanbrandhorst

src/runtime/internal/wasitest/tcpecho_test.go

@@ -44,9 +44,9 @@ func TestTCPEcho(t *testing.T) {
 	subProcess.Env = append(os.Environ(), "GOOS=wasip1", "GOARCH=wasm")
 
 	switch os.Getenv("GOWASIRUNTIME") {
-	case "wazero", "":
+	case "wazero":
 		subProcess.Env = append(subProcess.Env, "GOWASIRUNTIMEARGS=--listen="+host)
-	case "wasmtime":
+	case "wasmtime", "":
 		subProcess.Env = append(subProcess.Env, "GOWASIRUNTIMEARGS=--tcplisten="+host)
 	default:
 		t.Skip("WASI runtime does not support sockets")