Remove unnecessary #undef about q{Debug,Info,Warning,Critical,Fatal}

The ones in qlogging.cpp were copied to it from qglobal.cpp in commit
23688d8942. They existed in qglobal.cpp
like in qdebug.cpp since the beginning of the public history. The one in
qdebug.cpp already made no sense in Qt 4 times, because qdebug.cpp was a
documentation-only source (no actual C++ code).

The #undefs from qglobal.cpp hadn't been necessary since commit
d394ca7f27, the global functions qDebug(),
qWarning(), qCritical(), etc. were replaced by member functions in
QMessageLogger whose names did not match the macros.

Pick-to: 6.7
Change-Id: I50e2158aeade4256ad1dfffd17b1c62f23eca4db
Reviewed-by: Kai Köhne <kai.koehne@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

src/corelib/global/qlogging.cpp

@@ -374,7 +374,6 @@ static void qt_message(QtMsgType msgType, const QMessageLogContext &context, con
         qt_message_fatal(msgType, context, buf);
 }
 
-#undef qDebug
 /*!
     Logs a debug message specified with format \a msg. Additional
     parameters, specified by \a msg, may be used.
@@ -389,8 +388,6 @@ void QMessageLogger::debug(const char *msg, ...) const
     va_end(ap);
 }
 
-
-#undef qInfo
 /*!
     Logs an informational message specified with format \a msg. Additional
     parameters, specified by \a msg, may be used.
@@ -619,7 +616,6 @@ QDebug QMessageLogger::info(QMessageLogger::CategoryFunction catFunc) const
 
 #endif
 
-#undef qWarning
 /*!
     Logs a warning message specified with format \a msg. Additional
     parameters, specified by \a msg, may be used.
@@ -725,8 +721,6 @@ QDebug QMessageLogger::warning(QMessageLogger::CategoryFunction catFunc) const
 
 #endif
 
-#undef qCritical
-
 /*!
     Logs a critical message specified with format \a msg. Additional
     parameters, specified by \a msg, may be used.
@@ -833,8 +827,6 @@ QDebug QMessageLogger::critical(QMessageLogger::CategoryFunction catFunc) const
 
 #endif
 
-#undef qFatal
-
 /*!
     Logs a fatal message specified with format \a msg for the context \a cat.
     Additional parameters, specified by \a msg, may be used.

src/corelib/io/qdebug.cpp

@@ -2,13 +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
 
-#ifdef QT_NO_DEBUG
-#undef QT_NO_DEBUG
-#endif
-#ifdef qDebug
-#undef qDebug
-#endif
-
 #include "qdebug.h"
 #include "private/qdebug_p.h"
 #include "qmetaobject.h"