x/telemetry: make counter, upload operations no-op on platforms not covered in testing

[hyangah]

See GOOS/GOARCH excluded from telemetry library's testing.

https://go.googlesource.com/telemetry/+/refs/heads/master/internal/testenv/testenv.go#58

Related #65447

[matloob]

This should be fixed by golang.org/cl/560462