tools: make cmd/tools/vretry_test.v independent from the presence of git (fix issue #23398)

cmd/tools/check_retry.vsh

@@ -0,0 +1,13 @@
+#!/usr/bin/env -S v -raw-vsh-tmp-prefix tmp
+
+// This script is used by cmd/tools/vretry_test.v, to check that the `v retry`
+// subcommand works as expected, without relying on external commands like
+// `git`, or on non portable ones like `true`/`false` or `echo`.
+
+fn main() {
+	args := arguments()#[1..]
+	println(args)
+	if args == ['too', 'many', 'arguments'] {
+		exit(1)
+	}
+}