Unit tests: Remove mbed.h stub from target_h

The header `mbed.h` is a convenient wrapper that pre-includes some
platform headers, for use by user applications. Libraries and tests
internal to Mbed OS should not use it, and they should explicitly
include headers they need. So a stub is not needed.

UNITTESTS/target_h/mbed.h

@@ -1,34 +0,0 @@
-/*
- * Copyright (c) 2018, Arm Limited and affiliates.
- * SPDX-License-Identifier: Apache-2.0
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#ifndef MBED_H
-#define MBED_H
-
-#include <cstdio>
-#include <cstring>
-
-#include "events/mbed_events.h"
-#include "events/mbed_shared_queues.h"
-
-namespace mbed {
-#include "platform/Callback.h"
-};
-
-using namespace mbed;
-using namespace std;
-
-#endif // MBED_H

connectivity/netsocket/tests/UNITTESTS/doubles/NetworkStack_stub.cpp

@@ -17,7 +17,6 @@
 
 #include "netsocket/NetworkStack.h"
 #include "netsocket/nsapi_dns.h"
-#include "mbed.h"
 #include "stddef.h"
 #include <new>
 

events/tests/UNITTESTS/equeue/test_equeue.cpp

@@ -16,7 +16,7 @@
  */
 #include "gtest/gtest.h"
 #include "events/equeue.h"
-#include "mbed.h"
+#include "platform/Callback.h"
 #include <unistd.h>
 #include <pthread.h>