[Reproducers] Include lldb version in the reproducer root

Generally, reproducers are rev-locked to the version of LLDB, so it's
valuable to have the LLDB version in the reproducer. For now I just want
the information to be present, without enforcing it, but I envision
emitting a warning during replay in the future.

Differential revision: https://reviews.llvm.org/D63229

git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@363225 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed