## Why
The Windows PTY implementation probed `conpty.dll` by bare name. Windows could
resolve that lookup to a DLL in the process current directory and load it when
creating a pseudoconsole.
## What changed
Resolve the ConPTY entry points from `kernel32.dll` without probing
`conpty.dll`.
## Testing
Add a Windows regression test that places a compatible `conpty.dll` in the
current directory, creates a ConPTY, and verifies that the DLL was not loaded.
GitOrigin-RevId: be78974362a99dce0c18186cf3e7bbd86a8de73c
