Derive the proxy tests' short timeout setting from the timeout (closes #61)

shortTimeoutSetting is now shortTimeout.String(), so changing waitLimit
changes both together.

Model: opus-5-5

internal/proxy/proxy_test.go

@@ -26,8 +26,6 @@ const (
 	// test process that wantTimedOut allows: a shorter one can run out
 	// first on a busy host.
 	shortTimeout = waitLimit / 2
-	// shortTimeoutSetting is shortTimeout as a setting's value.
-	shortTimeoutSetting = "5s"
 	// longTimeoutSetting is a timeout that does not run out in a test.
 	longTimeoutSetting = "1m"
 	// waitLimit bounds how long a test waits for what should happen.
@@ -39,6 +37,11 @@ const (
 	localhost = "127.0.0.1"
 )
 
+// shortTimeoutSetting is shortTimeout as a setting's value.
+//
+//nolint:gochecknoglobals // a constant cannot call String
+var shortTimeoutSetting = shortTimeout.String()
+
 // The settings the tests set.
 const (
 	clientRequestTimeout    = "SWWAF_CLIENT_REQUEST_TIMEOUT"