[Reproducer] Instruct users to replay reproducer

Improve the message printed when LLDB crashes by asking the user to
replay the reproducer before attaching it to a bugreport..

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Crash reproducer for lldb version 10.0.0 (git@github.com:llvm/llvm-project.git revision ...)
  clang revision ...
  llvm revision ...

Reproducer written to '/path/to/reproducer'

Before attaching the reproducer to a bug report:
 - Look at the directory to ensure you're willing to share its content.
 - Make sure the reproducer works by replaying the reproducer.

Replay the reproducer with the following command:
./bin/lldb -replay /path/to/reproducer
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