tests: fix compilation with osx/clang, avoid implicit conversion

- osx clang does not support sending a newly created string to
   an ostream, converting it to c_str
 - avoid std::string(QBytearray), as that skips length (I suppose)

Change-Id: I3712df9d5e4a6f96420a8f2bf59c3bec9286b788
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>

tests/tools/cplusplus-ast2png/cplusplus-ast2png.cpp

@@ -57,6 +57,7 @@
 #include <cstdlib>
 #include <fstream>
 #include <iostream>
+#include <string>
 #ifdef __GNUC__
 #  include <cxxabi.h>
 #endif
@@ -115,7 +116,7 @@ protected:
     void alignTerminals() {
         out<<"{ rank=same;" << std::endl;
         foreach (const QByteArray &terminalShape, _terminalShapes) {
-            out << "  " << std::string(terminalShape) << ";" << std::endl;
+            out << "  " << std::string(terminalShape.constData(), terminalShape.size()).c_str() << ";" << std::endl;
         }
         out<<"}"<<std::endl;
     }

tests/tools/qml-ast2dot/main.cpp

@@ -43,6 +43,7 @@
 #include <cstdlib>
 #include <fstream>
 #include <iostream>
+#include <string>
 #ifdef __GNUC__
 #  include <cxxabi.h>
 #endif
@@ -83,7 +84,7 @@ protected:
     void alignTerminals() {
         out<<"{ rank=same;" << endl;
         foreach (const QByteArray &terminalShape, _terminalShapes) {
-            out << "  " << string(terminalShape) << ";" << endl;
+            out << "  " << string(terminalShape.constData(), terminalShape.size()).c_str() << ";" << endl;
         }
         out<<"}"<<endl;
     }