Utils: Merge {synchronous,qtc}process.{h,cpp} file pairs

Mechanical to prepare merging the actual classes.
Adapting #includes.

Change-Id: I77a2c28129287778bc870c30cb890cd26bc2e62b
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/libs/utils/pathchooser.cpp

@@ -26,11 +26,10 @@
 #include "pathchooser.h"
 
 #include "environment.h"
-#include "qtcassert.h"
-#include "macroexpander.h"
-
-#include "synchronousprocess.h"
 #include "hostosinfo.h"
+#include "macroexpander.h"
+#include "qtcassert.h"
+#include "qtcprocess.h"
 #include "theme/theme.h"
 
 #include <QDebug>