[Tooling] Wait for all threads to finish before resetting CWD.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@342028 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Tooling/AllTUsExecution.cpp

@@ -129,6 +129,8 @@ llvm::Error AllTUsToolExecutor::execute(
           },
           File);
     }
+    // Make sure all tasks have finished before resetting the working directory.
+    Pool.wait();
     if (!InitialWorkingDir.empty()) {
       if (auto EC = llvm::sys::fs::set_current_path(InitialWorkingDir))
         llvm::errs() << "Error while restoring working directory: "