Break qglobal.h cyclic includes [3/3]

... with q*atomic.h.

Drive-by change: include <climits> instead of <limits.h>, from the
former's docs:
«This is a Standard C++ Library file.  You should @c \#include this
file in your programs, rather than any of the @a *.h implementation
files.»

Task-number: QTBUG-106722
Change-Id: Id8169c482d2231c1620db033fbed1f904e15ed9c
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/thread/qatomic.h

@@ -2,8 +2,6 @@
 // Copyright (C) 2016 Intel Corporation.
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
-#include <QtCore/qglobal.h>
-
 #ifndef QATOMIC_H
 #define QATOMIC_H
 

src/corelib/thread/qbasicatomic.h

@@ -2,8 +2,6 @@
 // Copyright (C) 2018 Intel Corporation.
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
-#include <QtCore/qglobal.h>
-
 #ifndef QBASICATOMIC_H
 #define QBASICATOMIC_H
 

src/corelib/thread/qgenericatomic.h

@@ -5,7 +5,6 @@
 #ifndef QGENERICATOMIC_H
 #define QGENERICATOMIC_H
 
-#include <QtCore/qglobal.h>
 #include <QtCore/qtypeinfo.h>
 
 QT_BEGIN_NAMESPACE

src/corelib/tools/qcontiguouscache.cpp

@@ -6,6 +6,8 @@
 #include <QDebug>
 #endif
 
+#include <QtCore/qmalloc.h>
+
 QT_BEGIN_NAMESPACE
 
 #ifdef QT_QCONTIGUOUSCACHE_DEBUG

src/corelib/tools/qcontiguouscache.h

@@ -5,7 +5,12 @@
 #define QCONTIGUOUSCACHE_H
 
 #include <QtCore/qatomic.h>
-#include <limits.h>
+#include <QtCore/qassert.h>
+#include <QtCore/qtclasshelpermacros.h>
+#include <QtCore/qtcoreexports.h>
+
+#include <climits>
+#include <limits>
 #include <new>
 
 QT_BEGIN_NAMESPACE