This bug was surfaced by #19960 because benchmarks shouldn’t have run
TestListenService, but they did because PowerShell interpreted match
empty string `"^$"` as beginning of string `'^'`.
This patch has the Windows build run `./tool/go` binaries with bash
and synchronizes it with the *nix `bench all` run.
Updates #18884
Updates #19960
Signed-off-by: Simon Law <sfllaw@tailscale.com>