This is a follow up to https://github.com/llvm/llvm-project/pull/162509.
Using the `SearchPathW` API, we can ensure that the correct version of
Python is installed before `liblldb` is loaded (and `python.dll`
subsequently). If it's not, we try to add it to the search path with the
methods introduced in https://github.com/llvm/llvm-project/pull/162509.
If that fails or if that method is `#ifdef`'d out, we print an error
which will appear before lldb crashes due to the missing dll.
Before https://github.com/llvm/llvm-project/pull/162509, when invoked
from Powershell, lldb would silently crash (no error message/crash
report). After https://github.com/llvm/llvm-project/pull/162509, it
crashes without any indications that the root cause is the missing
python.dll. With this patch, we print the error before crashing.
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