Bumping up signing attempts limit to 5 to give more time for computation

pkg/tbtc/signing_test.go

@@ -185,7 +185,7 @@ func setupSigningExecutor(t *testing.T) *signingExecutor {
 
 	// Test block counter is much quicker than the real world one.
 	// Set more attempts to give more time for computations.
-	executor.signingAttemptsLimit *= 3
+	executor.signingAttemptsLimit *= 5
 
 	return executor
 }