Fix Windows path parsing when the package is built in release configuration

forceWindowsPaths can be used to force Windows path parsing both on and off.
Instead of defaulting it to false in release builds, we should not express any preference

Author: owenv

Sources/System/Internals/Mocking.swift

@@ -130,7 +130,7 @@ internal var mockingEnabled: Bool {
 @inline(__always)
 internal var forceWindowsPaths: Bool? {
   #if !ENABLE_MOCKING
-  return false
+  return nil
   #else
   return MockingDriver.forceWindowsPaths
   #endif