Tests: Don't use nm to look for symbols in an object built by MSVC.
Tests: Don't use nm to look for symbols in an object built by MSVC.

We relied on nm not being available on Windows, but it can be if mingw
is installed.

Change-Id: I13a93a7a3b54129f75e1a746a09c9abd9f89ee33
Reviewed-by: Joerg Bornemann <47777b9406dbddd02a3fdca8341789a013805a11@digia.com>

qt-labs/qbs,villytiger/qbs,qt-labs/qbs,Distrotech/qbs,gatzka/qt-labs-qbs,villytiger/qbs,qtproject/qt-labs-qbs,Distrotech/qbs,qtproject/qt-labs-qbs,Distrotech/qbs,Distrotech/qbs,qt-labs/qbs,qtproject/qt-labs-qbs,qtproject/qt-labs-qbs,gatzka/qt-labs-qbs,Distrotech/qbs,qtproject/qt-labs-qbs,qtproject/qt-labs-qbs,gatzka/qt-labs-qbs,villytiger/qbs,qt-labs/qbs,Distrotech/qbs,qt-labs/qbs,gatzka/qt-labs-qbs,villytiger/qbs,qt-labs/qbs,qt-labs/qbs,gatzka/qt-labs-qbs,villytiger/qbs,gatzka/qt-labs-qbs,qtproject/qt-labs-qbs,villytiger/qbs,gatzka/qt-labs-qbs,Distrotech/qbs