Debugger: Remove support for non-Python GDB

This affects mainly Apple's version of GDB. Mac users are advised to
use LLDB, or some recent build of FSF GDB.

Change-Id: I6a7fbb591e79f737e12d08b0e881e9e4d1d9660c
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>

src/plugins/debugger/gdb/gdbplainengine.cpp

@@ -112,13 +112,6 @@ void GdbPlainEngine::handleExecRun(const GdbResponse &response)
     }
 }
 
-GdbEngine::DumperHandling GdbPlainEngine::dumperHandling() const
-{
-    // LD_PRELOAD fails for System-Qt on Mac.
-    return Utils::HostOsInfo::isWindowsHost() || Utils::HostOsInfo::isMacHost()
-            ? DumperLoadedByGdb : DumperLoadedByGdbPreload;
-}
-
 void GdbPlainEngine::setupEngine()
 {
     QTC_ASSERT(state() == EngineSetupRequested, qDebug() << state());