Remove a misleading comment

Author: Max Moiseev

benchmark/utils/main.swift

@@ -10,13 +10,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-////////////////////////////////////////////////////////////////////////////////
-// WARNING: This file is manually generated from .gyb template and should not
-// be directly modified. Instead, make changes to main.swift.gyb and run
-// scripts/generate_harness/generate_harness.py to regenerate this file.
-////////////////////////////////////////////////////////////////////////////////
-
 // This is just a driver for performance overview tests.
+
 import TestsUtils
 import DriverUtils
 import Ackermann