[intel-mpx] Delete an unnecessary license header

Summary:
@labath mentioned to me that test files shouldn't have a license header.
I saw this one some days ago, so I'm doing some cleaning.

Reviewers: labath, clayborg

Subscribers: lldb-commits, labath

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D77328

lldb/tools/intel-features/intel-mpx/test/main.cpp

@@ -1,12 +1,3 @@
-//===-- main.cpp ------------------------------------------------*- C++ -*-===//
-////
-//// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-//// See https://llvm.org/LICENSE.txt for license information.
-//// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-////
-////===----------------------------------------------------------------------===//
-//
-
 const int size = 5;
 
 #include <cstddef>