[lldb] Add windows support for LLDB_EXPORT_ALL_SYMBOLS (#67628)

LLDB_EXPORT_ALL_SYMBOLS is useful when building out-of-tree plugins and
extensions that rely on LLDB's internal symbols. For example, this is
how the Mojo language provides its REPL and debugger support.

Supporting this on windows is kind of tricky because this is normally
expected to be done using dllexport/dllimport, but lldb uses these with
the public api. This PR takes an approach similar to what LLVM does with
LLVM_EXPORT_SYMBOLS_FOR_PLUGINS, and what chromium does for
[abseil](https://github.com/chromium/chromium/blob/253d14e20fdc0cab05e5516770dceca18f9bddaf/third_party/abseil-cpp/generate_def_files.py),
and uses a python script to extract the necessary symbols by looking at
the symbol table for the various lldb libraries.