Utils: Drop unused headers [A-H]

Round 2 - focus on sources.
For classes with initial in range [A-H].
Try to keep the same separators between different kind of headers.

Change-Id: I838a8324ddd5b4d8d5a51b8f30605f783c663813
Reviewed-by: hjk <hjk@qt.io>

src/libs/utils/environment.cpp

@@ -29,11 +29,9 @@
 #include "fileutils.h"
 #include "qtcassert.h"
 
-#include <QDebug>
 #include <QDir>
 #include <QProcessEnvironment>
 #include <QSet>
-#include <QCoreApplication>
 
 namespace Utils {