HHH-12778 Register the cause when an exception occurs creating a proxy

Author: gsmet

hibernate-core/src/main/java/org/hibernate/bytecode/internal/bytebuddy/BasicProxyFactoryImpl.java

@@ -54,7 +54,7 @@ public Object getProxy() {
 return proxy;
 }
 catch (Throwable t) {
-throw new HibernateException( "Unable to instantiate proxy instance" );
+throw new HibernateException( "Unable to instantiate proxy instance", t );
 }
 }