QLogging: exclude QInternalMessageLogContext from backtraces

"Just in case" -- as the comment says,
QInternalMessageLogContext's constructor is usually inlined, but
we can't be sure if it has been.

Change-Id: I4da2f0875d9fd9f7bd6d79447b4761fda329c7fd
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/global/qlogging.cpp

@@ -1375,6 +1375,8 @@ backtraceFramesForLogMessage(int frameCount,
             return true;
         if (function.contains("17qt_message_output"_L1))
             return true;
+        if (function.contains("26QInternalMessageLogContext"_L1))
+            return true;
         return false;
     };