[clang] Fix for a clang-repl crash when passing non-existent file to --Xcc (PR #225861)

[Vassil Vassilev via cfe-commits]

================
@@ -127,6 +127,10 @@ class Interpreter {
   /// An optional compiler instance for CUDA offloading
   std::unique_ptr<CompilerInstance> DeviceCI;
 
+  /// This member is set when source file has been successfully created. It
+  /// will be used to gate 'ending' this file when the object is destroyed.
+  bool SourceFileCreated = false;
----------------
vgvassilev wrote:

Do we need a special flag to deduce that information?

https://github.com/llvm/llvm-project/pull/225861