sww tests: wait for every starting line as long as the start takes (closes #331)

Tests only, in `internal/sww`. Every wait for the `starting` line now uses `output.lineBeforeExit`, which waits until the line is written or sww exits, so a slow Core Rule Set compile on a loaded host no longer fails these tests. `TestMainRunsWAF` and `startRProxyProcess` start sww through `startProcess`, whose cleanup kills sww as the test ends and waits for it to exit; `startRProxyProcess` returns a stop function that sends SIGTERM and fails the test unless sww exits with status 0 within `waitLimit`.

Model: opus-5-5

internal/sww/healthcheck_test.go

@@ -41,7 +41,7 @@ func TestHealthCheckInWAFsContainer(t *testing.T) {
 		exited <- run(ctx, settings, out)
 	}()
 
-	addr, _ := out.line(t, "msg", "starting")["address"].(string)
+	addr, _ := out.lineBeforeExit(t, "starting", exited)["address"].(string)
 	_, port, _ := net.SplitHostPort(addr)
 
 	// The container's settings: an address to listen on with an empty