[lldb/Util] Add a utility to run transparently capture and replay tests.

This patch introduces a small new utility (lldb-repro) to transparently
capture and replay debugger sessions through the command line driver.
Its used to test the reproducers by running the test suite twice.

During the first run, it captures a reproducer for every lldb invocation
and saves it to a well-know location derived from the arguments and
current working directory. During the second run, the test suite is run
again but this time every invocation of lldb replays the previously
recorded session.

Differential revision: https://reviews.llvm.org/D72823