ClangTools: Use CtrlC Stub for clang tools on Windows

We got a report that using a clang-tidy would launch llvm-tokenizer,
which would not close when clang-tidy closes.

This resulted in zombie processes which would significantly
affect performance.

Change-Id: I1952be668b6352970cdb70c7fa622df77c2d175e
Reviewed-by: hjk <hjk@qt.io>

src/plugins/clangtools/clangtoolrunner.cpp

@@ -67,6 +67,7 @@ void ClangToolRunner::init(const FilePath &outputDirPath, const Environment &env
     QTC_CHECK(!m_outputDirPath.isEmpty());
 
     m_process.setEnvironment(environment);
+    m_process.setUseCtrlCStub(true);
     m_process.setWorkingDirectory(m_outputDirPath); // Current clang-cl puts log file into working dir.
     connect(&m_process, &QtcProcess::done, this, &ClangToolRunner::onProcessDone);
 }