ptests: Fix qlogging to use relative folder

Run qlogging_helper at relative working directory because
CMAKE_CURRENT_BINARY_DIR is not valid when test is run after
installed from package to target.

Task-number: QTBUG-118680
Change-Id: Ifd46d05562006ad4adf17517fae30ca5c63bc157
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

tests/auto/corelib/global/qlogging/CMakeLists.txt

@@ -23,7 +23,6 @@ set_target_properties(qlogging_helper PROPERTIES CXX_VISIBILITY_PRESET default)
 qt_internal_add_test(tst_qlogging SOURCES tst_qlogging.cpp
     DEFINES
         QT_MESSAGELOGCONTEXT
-        HELPER_BINARY="${CMAKE_CURRENT_BINARY_DIR}/qlogging_helper"
 )
 
 add_dependencies(tst_qlogging qlogging_helper)

tests/auto/corelib/global/qlogging/tst_qlogging.cpp

@@ -986,11 +986,9 @@ QString tst_qmessagehandler::backtraceHelperPath()
 #ifdef Q_OS_ANDROID
     QString appExe(QCoreApplication::applicationDirPath()
                    + QLatin1String("/lib" BACKTRACE_HELPER_NAME ".so"));
-#elif defined(Q_OS_WEBOS)
+#else
     QString appExe(QCoreApplication::applicationDirPath()
                    + QLatin1String("/" BACKTRACE_HELPER_NAME));
-#else
-    QString appExe(QLatin1String(HELPER_BINARY));
 #endif
     return appExe;
 }