Process: Introduce rawStdErr()

Complementary to rawStdOut().

Change-Id: I621b5b9858f775139a2c900f06812d9dd249d034
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

src/libs/utils/process.h

@@ -171,6 +171,7 @@ public:
     QString allOutput() const;
 
     QByteArray rawStdOut() const;
+    QByteArray rawStdErr() const;
 
     QString stdOut() const; // possibly with CR
     QString stdErr() const; // possibly with CR